The G-Man wakes up Gordon from his sleep, and has a talkwith him before teleporting him into a train car. It seems that Gordon is being sent to City 17. Step off the train to encounter some Scanners (they'll only take a photo of Gordon though).

After noticing the former Administrator of Black Mesa on the screen, move left and through the revolving door. Enter the room with a lot of lockers and talk to the many people there.

Move into the line and wait. The Cops will bring Gordon through the fences. Step up to the train going to Nova Prospekt. It doesn't seem that Gordon won't be going there, yet. Another Civil Protection guy wants Gordon to follow him (he has a different voice from the rest of the CPs, apparently).

Inside the room with the barber chair on it, the CP will be left alone and he will deactivate the cameras. It's Barney Calhoun! He says that he's been working in the Civil Protection Unit undercover. He'll contact Dr. Kleiner and Kleiner will suggest Gordon to go to his lab. Barney escorts Gordon (hastily) to a room with a bunch of boxes in it.

Climb the ladder and grab a box (E). Bring it to the window and jump through. Move into the building and up the stairs. Run into a CP and he'll order Gordon to pick up a Can. Do what he says and move on (or throw the can right at his face and run away!). Ignore the delivery line and move left and out to the plaza.

The only way to go is right towards an alley, all other routes are blocked by the Combine fields. Climb the ladder and the down to the other side of the fence. Turn right and talk to the two guys on their porch. Looks like the house ahead is being searched. Move towards the CPs and then left, up the stairs in the building.

In the apartment hallway, feel free to talk with the people in the rooms. Then go up the stairs and to the guy at the hallway. Looks like there's been an uproar, and Gordon is the target! Run away from the CPs! Move up the stairs with the cops in pursuit, and a frantic guy orders Gordon to get to the roof.

At the attic, climb out of the hole and across the rooftops. Hop into another attic and move down the stairs. Gordon's cornered (or sandwiched, or something)! Fortunatley, a young teenage girl manages to kill the CPs with martial arts. She's Alyx Vance, the girl Kleiner mentioned. Go down the elevator with her and she'll talk things over. Keep following her. She'll get Gordon all caught up with most of the cast of characters in the game.

Again, keep following Alyx and listening to her small talk. She says that Gordon's friends have been helping Citizens get across away from the Combine. Today, they're experimenting with a teleporter. After discovering a secret passage (marking Lambda Cache 1), get into the lab and meet Dr. Kleiner (in person). It seems that his pet is missing. He'll start talking over with Alyx. Pretty soon, Barney will come. Explore the room. Gordon can mess around with Kleiner's mini-teleporter, and even break it (uh-oh)!.

After a while, Kleiner will tell Barney to get Gordon's HEV suit ready. It seems that Kleiner's pet, Lamarr (a Headcrab) has been hiding here all along. After Lamarr jumps into the vent, get the HEV Suit. Get it charged at the other end of the room, and move onto the teleporter room. Feel free to take a look at the monitor (and see the G-Man disappear from the premises).

After meeting Eli Vance, Alyx will climb onto the teleporter. In the teleportation process, a plug will pop out. Plug it back in and activate the switch. Alyx will be safely teleported to Black Mesa East. Get onto the teleporter.

Gordon's about to be teleported, but Lamarr will suddenly appear out of a vent and teleport Gordon to various places, including Black Mesa East, Breen's Office, and even a nasty encounter with an Ichthyosaur!

Later, Gordon will be teleported outside of Kleiner's Lab. After the teleportation sequence is done, run away from the Scanners! Run into the building and up the stairs!

Barney will appear on top of the building. Take a look at the Citadel (that big tall tower in the city). Millions of Scanners are going out! Barney tells Gordon to run through the canals to Black Mesa East. He also hands Gordon his trusty Crowbar. Use it to smash through the 2 by 4s blocking the entrances.

There's nothing Gordon can do to the CPs, but he can smash the Scanners. Move through the freight cars. Smash through the various wooden obstacles inside, and avoid the incoming train on the rails! One of the boxcars will have a ladder leading to the top. From here, hop over the fence and into the dark hallways.

This chapter, along with Ravenholm, is one of the scariest, thanks to the dark sewers and the Manhacks! Gordon will be fighting with the CPs here.

Use the Health Station in the hallway, then ambush the two CPs attacking a citizen. Grab the Pistol and smash through the wood. Kill the two CPs while going up the stairs.

Go down the stairs outside and then back up when Gordon hears a train whistle. Once the train comes to a complete stop, hop onto the tanker and then across the cars to the ladder on the other side (or jump on while the train is still moving, and then hastily jump to said ladder). Smash the Scanner in the building, nab the supplies (Lamda 2), and shoot the Barrels the CPs are next to the ridge above.

Move left and then dispatch the CPs on the other side (where Gordon used to be). Feel free to shoot the Explosive Barrels near them. Go across and crawl through the vent (here is Lambda 3), then drop down on the tracks.

Shoot the Barrel that comes down the stairs, then grab anything useful there. Go left and on the catwalk, which will lead to the other side of the tracks that are blocked by the suppresion field. Stop by the alcove to the side, and grab anything useful there.

Jump into the water canal, and keep swimming to the boxcar. Hop in and talk with the Citizen and Vortigaunt. The Vortigaunt will give Gordon an armour boost, and the Citizen will tell Gordon that there are many Citizen Stations throughout the area. Move out and destroy the blockade (whack some of the boards to make the rest of the blockade collapse).

Dispatch the Barnacle eating the crow and run into a station being attacked by CP Units. Keep advancing and then once a nasty Machine Gun emplacement is in sight, move into the sewer pipe leading to a room with a radio (and some CPs).

Listen to the radio (something about Combine closing in on the Underground Railroad and Manhacks), collect the supplies, and climb the ladder to sneak up on the Cops next to the Machine Gun.

Use it to fend off the Combine forces in this area (CPs will appear at the canal's floor, and the bridge. Scanners will come from the sky). An APC will soon drive by and destroy the Gun Emplacement.

Before this happens, use it to destroy the barrel to the right, which will make a platform collapse on the walkway on the right, allowing Gordon to cross to the other side of the rubble on the opposite end of the canal.

There's a Lambda Cache in the car in this area (Lambda 4), then advance. There is a Station survivor in the concrete pipe, who says that there's more stations up ahead (much like the American Underground Railroad).

Run through the pipe and look up to find two CP officers talking. Jump up to the next pipe (Gordon will get spotted by the cops) and jump into the water. The CPs will toss in some Explosive Barrels. Stay away from the barrels, and then shoot the two CPs above.

After climbing up the pipe, turn right and shoot down the CPs. There is some Explosive Barrels under the bridge; blow it up to neutralize an entire squad of CPs. Once all enemies are dead, crawl through the pipe.

The floor is slippery. Be sure not to run into the tongues of the Barnacles up above. Ahead is an entire cluster of Barnacles. Throw an Explosive Barrel at one of their tongues, and then light it up when it gets close enough to the ceiling. Slide over to the outdoors and avoid the gunfire. The CPs will throw more explosive barrels. Get to the opposite side of the water (there's a ladder that will allow Gordon to get to the other side of the underwater fence). Once there, go up the ramp, eliminating any CPs on the way. Jump across the platforms to the pipe on the end.

In this room, stack the concrete blocks on the see-saw on the side opposite of the tunnel. Jump on that side, then run to the other side and jump to the next tunnel (Gordon can also stack the blocks to make a flight of stairs).

Outside, turn left and keep going down. Shoot down the Scanner. Go down the path to the left. While the Helicopter is trying to gun Gordon down, get into cover before it fires. Go up the ramp and into the sewers. Go down the ladder for some supplies (Lambda 5). Climb the ladder up again and face the fence. Turn left. Step forward and turn right. Throw an Explosive Barrel to the Barnacles, then kill them. Keep heading through the sewers. Outside, turn left and keep running across the path.

Move through the hallways, and meet up with a lonely Citizen (after breaking a wooden barricade). He says that the Combine have released their Manhacks. It seems that the Manhacks have made their way here. Use the Pistol or the Crowbar and destroy all of the Manhacks. Grab all the supplies in this room afterwards. Move foreward to find more Manhacks advancing through a hallway full of boxes. Shoot them beyond the fence.

The next hallway has some explosive barrels. Detonate the barrels to destroy the Manhacks nearby. Keep advancing through the hallways, and head outside. Push the debris out of Gordon's way so he can get through the door. Barricade the door so the Manhacks behind can't get through.

Climb into the vent to find more supplies (and a Manhack). Return and kill the CP here, then hop down to the water. Some CPs armed with MP7s jump down from above! Dispatch them and nab their MP7s. In the little hole in the wall, there's a Zombie and a Grenade. Return and kill more CPs roping down. Run across the hallways and jump into the water. To the left is a hole where Gordon can swim to the next area.

This area has a pipe. Run perpedicular to the pipe and up the stairs so that Gordon can hop onto the next level. He can now jump onto the pipe from here! on the pipe, walk to the other end. Wait for the steam to stop, then run across. At the end of the pipe, destroy the Manhack. Smash the wood, then hop down.

Underneath the pipe is some supplies (Lambda 6). There is also a hole that leads downward. Jump in the water near the hole and resurface outdoors. Shoot the barrels ahead when they are in sight, ASAP. Kill the CPs on the bridge.

To the right is a narrow corridor that has a door. Behind that door are more Manhacks! Use a Grenade and throw it beyond the door. Destroy any surviving Manhacks. Advance through the door, collect the supplies, then crawl through the vent.

Oh noes! Gordon is now in a dark, smelly room full of Explosive Barrels and Manhacks! Shoot the barrels, and deal with any Manhacks. Once the place is completley Manhack-free, climb the ladder, and hop onto the pipe. Walk across the pipe to the upper areas of the room, which lead to the next area.

In this area, at the bottom in the water, there are some Medkits. Among the many pipes is a valve. Climb down the pipes and turn the valve. This will make the water level rise. Head back to the previous room. More Manhacks will come through the vents! Destroy them, then head down underwater and through the large pipe.

Right now, there's no way to get to the exit. Swim down and break the pieces of wood to release an object that will float to the top. Jump across the water to the object once at water level and then jump to the exit.

Jump down into the canal and shoot any Scanners or Manhacks. Some CPs will also drop down. Head towards the CPs after dispatching them, then climb up left. Collect the supplies and head through the hallway. More Manhacks will chop through the boxes. Destroy them at once!

There's a small hole with Barnacles overlooking Supplies (Gordon should do what he does best here). Climb up the ladder in the next place and then drop down at the end (after obtaining Lambda 7). Head outdoors AGAIN.

Be sure to avoid the liquidy part of the radioactive waste below. Climb up the pipe to find more supplies (Lambda 8). Meet up with the resistance fighter fighting off some headcrabs. Give him a helping hand. Alyx's voice comes on the radio soon after and mentions an Airboat. Leave the citizen behind after collecting the SMG ammo from the Ammo Box.

Run across the path, avoiding the waste. A Headcrab missile will kill the escaping citizens. Kill any Headcrabs that pop out of it. More Headcrabs will pop out of the ground throughout this area. Behind the fence is a citizen who has recently been attacked by a Headcrab. More Headcrabs will pop out of the missile in the ground. Head towards the liquidy area (but don't step ON it). The Zombies will awaken, so kill them. Keep advancing through the rubble, killing any Headcrabs and Zombies, and avoiding any obstacles in the way.

Here's a tip from Jayelgee:

"It IS possible (as an alternatative) to simply run through the yard, staying one step ahead of all enemies and avoiding any electrified wires or surfaces. Hanging around to fight enemies as they come exposes you to more background radioactivity, possibly depleting your health."

Eventually, Gordon will meet up with another Citizen who has geared up an Airboat. She will also mention a Red Barn. Grab the Airboat's bars and drive in the open! Open the gate up ahead (turn the wheel and kill the Headcrab to advance).

Another thing Jayelgee wanted to mention:

"Upon leaving the yard, you need to follow the boards on the ground to the LEFT, DO NOT HEAD TO THE RIGHT, or you could waste a lot of time roaming around the next area on foot, only to wind up stranded at the canal gate, with no Airboat to carry you further."

Gordon's only hope of crossing the Canals now is to use an Airboat through the many Combine Outposts. DO NOT DITCH IT. It is vital throughout the entire chapter.

After going through the gate, keep an eye out for a Lambda symbol. Climb up the ladder to find a Supply Box (Lambda 9). Return to the Airboat and to the Barn. The G-Man can be seen at the top of the Barn. A visit to the Barn is completley optional.

Inside the barn, kill any Zombies there (it's been destroyed). Climb up to the attic and kill the Headcrab. At the top of the Barn, break the plank of wood blocking the crane's control. This will drop the supplies the crane was carrying (Lambda 10). Go back down to the Airboat.

Continue driving until Gordon reaches a bridge (its arches that is). A Citizen will drop more supplies before being spied on by a Scanner. Shoot the Scanner (it will come towards Gordon).

There's another puzzle ahead. Jump into the pipe (not a Lambda Cache) and Gordon will end up above the pool. Drop the air barrels into the water. Put them underneath the box underwater that's attatched to the lever thingy. This will elevate the lever so that it will be level to the ground and the other end will point up to the higher level (the next area). Jump into the Airboat and speed on the lever and up to the next area!

There will be Combine Dropships dropping off Civil Protection Officers. Wait for the Dropship to leave, and dispatch the Cops. There's a Lambda Logo near the open pipe (Lambda 11), which will lead Gordon to a very dark area with a scary Zombie and Supplies.

Head back to the Airboat and keep zooming by the enemy Cops. Feel free to drive straight into the rickety supports to kill them. Keep driving through the linear path provided.

Gordon will soon encounter a Combine Base. There's a CP on the dock. Drive through the dock's supports (the ones that look like they could break) and then park on the concrete area with the ladder. Climb the ladder and head indoors. This may lead to a way to open the gate blocking the water way.

It looks like Breen is now aware of Gordon's presence. After watching his Breencast, head into the garage and search the rooms for supplies. In the garage, throw a Grenade through the glass to dispatch the CP and the many Manhacks. Use the First Aid Station if necessary.

Go outdoors to encounter a CP using a Machine Gun. Dispatch him (here, he might be fooled by a jar of mayonaise) and check the dumpster for another Supply Box.

Head through the door and shoot down the CPs there. Climb the other flight of stairs and though the third door. Shoot the Explosive Barrels to breach the gate.

The gate is open, and the alarm is sounding. Time to backtrack to the Airboat. There are squads of CPs ahead of the Machine Gun, and in the garage. Dispatch them, and try not to be overwhelmed. Man the Airboat.

Drive through the gate, and over the Supply Boxes (Gordon will somehow collect the goodies) and under the bridge, avoiding the CPs and gunfire. There's a secret in the pipes dead ahead under the APC (Lambda 12).

Keep advancing to find some more CPs attempting to block Gordon by putting the roadblock on fire. To the right is a ramp. Drive the Airboat on the ramp to make it over the fire safely. Turn right again and drive through the path, avoiding the cars and other obstacles (consider going under the wooden covers to be protected from the incoming Rockets!). Continue through the tunnel.

The supplies in the tunnel can be grabbed by placing the concrete blocks on the platform opposite of the one that's carrying the supplies (Lambda 13). There's another Combine checkpoint ahead (and of course, another closed gate).

Park the Airboat at the indoor dock with the door on it. Break the lock on the door and get inside. There's a Revolver in this room; use it on the CPs that barge through the next door. Collect the other supplies and head through the door and upstairs outdoors.

There's a Chopper outside! There's also many CPs too. Dispatch them (and any Manhacks they bring out). Climb up the stairs and hop on top of the boxes. On the boxes, hop to the other side of the warehouse. Of course, Gordon won't be alone while he does this. Kill every CP and Manhack that dares to lay a hand on our hero!

Gordon should now be encountering another CP behind a box. Dispatch him and two other CPs that come up the stairs. Go down the stairs, use the Stations to replenish Health and Armour, then head back outside. Stick to the right. This path leads to the control tower. Throw a Grenade up there and then take a Machine Gun to take down that Chopper! Once the Chopper is in full retreat, use the switch to open the gate.

Head back to the Airboat and drive through the gate. Another Helicopter will start dropping Bombs on Gordon, so keep moving! There's a Lambda Cache in an alcove to the left of the water path (Lambda 14). Head up the ramp and down to the other side of the wall. Drive into the pipe.

Outside, Gordon will have to race the Helicopter, avoiding the bombs on the way! Head through more pipes. There's a Lambda Cache that can be smashed down to the left (Lambda 15) in this area. The only way Gordon can pass through the next indoor area is to drive over the pipes below to the other side.

After heading outside again, turn right at the intersection and up the logs and up to the high area. Drive down off the elevation and turn right towards the tunnel. Drive towards the left wall in order to get up into the tunnel. Keep an eye out for a bit of green graffiti to the left in a certain water path (this will lead to Lambda 16).

Keep driving and then turn left at the water intersection towards the bridges (but not before searching an alcove to the left that leads to Lambda 17). Drive under them, driving into any CPs that grapple down. After going under the bridges, turn right. Drive up the ramp and inside the building. Collect the supplies and use the Stations. Then hop back into the Airboat and drive off the dock towards the door.

After going through the gate, turn left and see a missile cause a tower to collapse in Gordon's way. Drive over or under the rubble, then hit the gas towards the pipe, avoiding the APC's missiles on the way.

Steer right. The way forward is blocked by a wall. Use the lever near the flat ramp to activate an elevator that causes the ramp to angle upward. Find a ladder and climb it. Jump across towards the area above the elevator. There is a Laundry Machine here, so push it to the elevator. This will give the ramp enough elevation for Gordon to drive his Airboat over the wall.

Turn left and meet some friendly folk. They'll open the gate. Hop on the dock and talk with the male Rebel. He'll show Gordon a map. He's not too far from Eli's place, but it will be difficult for Gordon to get there with the Helicopter in livid pursuit. Therefore, the Rebel and his mates will give Gordon's Airboat a Machine Gun. Hop back onto the Airboat and drive through the gate, shooting the Barnacles on the way.

Drive through the rubble and shoot the Helicopter once spotted. Gordon will come across more docks. Instead of heading straight towards the gate, drive up the fence onto the dock, and drive up beyond the gate (Gordon can find some Supplies in the room the CPs came from). Keep driving across the river, killing any CPs on the way. Head into the tunnel.

Drive through the linear canal. Shoot down the APC's Rockets when driving off the ramp. Keep driving and shoot down the APC the Dropship is carrying. Turn right and shoot the Barnacles on the ceiling.

There's an intersection up ahead. Right leads to a dead-end with a bunch of Headcrabs, and some supplies in the planks above (Lambda 17).

Left leads forward. Go there and up the dirt towards the tunnel. The next notable area has many explosive Barrels and CPs. The Combine will attempt to stop Gordon with a fire wall. Drive past it and dodge the Barrels the CPs drop in Gordon's path. Make a U-turn and then turn right once Gordon is on the dock.

Go in and out the tunnel, then turn right. Gordon should now be in an area full of Boats and docks (the water level is very low here). Shoot the two APCs on the docks and then move under the docks. Inside the red box (it's in between the legs of the docks) are some explosive barrels. Shoot them to open the box and allow access via the Airboat. Drive through the box and under the docks, then drive on the ramp over the gap towards yet another pipe! Turn left then right.

Drive to an outdoor area full of rocks. Collect any supplies in this area before heading towards the gate. Soon, a Helicopter will be summoned, and it's Gordon's job to bring it down! Use the Machine Gun to shoot the Chopper once it's close enough. Once the Aircraft is damaged enough, it will start dropping countless bombs (and a Combine Soldier)! Eventually, it will be destroyed (avoid or shoot the Barrels on the ground during this process). Take a look at the dead Soldier, then head towards the gate.

Climb the ladder and use the wheel to open the gate. Drive the Airboat up the angled dock towards the Barracks. Shoot down the CPs inside, then collect the ammo (Gordon will need this). Drive to the dock over the river bridge (wait, was that the G-Man?) and then climb down the ladder towards the wall. Use the controls to open another gate, then return to the Airboat, drive down, and through the gate (by driving over the log).

In this area, Gordon can find a pipe (before heading to the Combine base) that leads to a Vortigaunt talking about philosophy. Dash through the radioactive waste in order to talk to him alive.

This is mainly a non-combat chapter. It also introduces new characters and a new weapon...

Park the Airboat at the dock and hop onto the concrete (Lambda 18). Head through the barrels and into the airlock (don't worry, the area inside is not flooded). Gordon will go through some security examinations, and will have a conversation with a female. This female, however, happens to be Dr. Mossman, Eli's associate (she was first seen when Gordon was in a teleportation malfunction). After the security check, follow Mossman into the elevator.

Welcome to Black Mesa East! Once the elevator has come to a complete stop, head towards Eli. After having more chit-chat, feel free to examine the room. The mentionable items in the room are:

-Eli's Family Picture.
-Judith Mossman (she's in the surveilance room).
-The jar with the head in it (it's actually deleted content).
-The bulletin.
-The Teleporter (Gordon could have skipped the Canals if it weren't for Lamarr!).
-The Xen sample.

Moments later, Alyx will enter the room. After a while (and an argument), Eli will suggest that Alyx and Gordon to head out to test "The Gravity Gun". Follow Alyx.

Now it is revealed that Alyx has a rivalry with Dr. Mossman. Also, she introduces a shadowy place named "Ravenholm". Getting closer to the gates leading to that place will have Alyx talk about it in more detail. Follow her to the airlock and outside. Alyx will hand Gordon the Gravity Gun. On the top balcony to the left is some Revolver Ammo and an old HEV Station plate. Use the Gravity gun to stack some stuff to get up there. After testing the Gravity Gun, follow Alyx (she'll take care of the walkthrough in this chapter).

Meet Alyx's companion, Dog (not a mammal). Play some Gravity-Frizbee for a bit. Dog will bring out his ball after a while (a disarmed Roller Mine, just so that we know). Keep playing fetch if necessary. Gordon can try scoring on the basketball net near Alyx (try shooting from afar for best results), or he can try punting it over the cliff!

After some games (and a brief bit of recklessness from Dog), some Scanners will come by! Run with Alyx to escape. In the airlock, Eli reveals that the Combine is attacking Black Mesa East! Follow Alyx until she and Gordon is separated by a chunk of ceiling that fell down to the floor.

Dog will open the door leading to Ravenholm to allow Gordon to escape from there. Use the Gravity Gun to push the locker blocking the hallway. Use the Crowbar to break the lock blocking the ladder (ignore the dead Headcrab). Climb up and into some horror...

Unlike the other chapters, Gordon will rarely encounter any Combine forces in here. Instead are endless swarms of Zombies, so Ammunition is scarce in this abandoned town. Gordon will need to utilize the Gravity Gun in order to survive through chopping Zombies and lighting them on fire. An Achievement is obtainable by only using the Gravity Gun (nope, not even the Crowbar is valid!)

Gordon finds himself in a backyard. Search the yard for Zombies, then head towards the building to the left. Smash through the wooden planks and observe the items here. Gas Containers and Sawblades; two lethal Anti-Zombie countermeasures. To the left is a room full of Zombies. Use the Blades and Containers to take them out. Go to the corridor on the right, then turn left.

Make the Barrels explode, then head outdoors. Gordon will start hearing human voices. Duck under the spinning blade and wait for some Zombies to meet an ignoble fate. Go up the stairs and knock the wooden plank off the doorway. Kill the Zombies in this room, and go out the doorway (after getting those stupid planks off of it).

Turn right, and toss a Barrel at the Zombie. In the next room, make the barrels explode, then take care of any remaining Zombies. Go out into the firey plaza. In the lighted room above, a bald man starts shooting at the Zombies at the plaza. Turn right and kill the zombies in this room. It looks like someone was up to some Zombie autopsies. Turn on the gas silo in this room to light a Zombie on fire. Head back out and turn off the gas silo to extinguish the fire. There's an electrified fence here. Kill the Zombies in this location and then return to the plaza.

There's another gas silo that's blocking Gordon's way. Turn it off and go into the building with turbines. Dispatch the Zombies in this area and hop onto the generators. Jump into the vent (this will lead to Lambda 19). Go back to the generator room and head to the stairwell.

Destroy the various bits of furniture blocking the stairs. Run up the stairs and turn left to see some seemingly dead Zombies. Attack any that has a Headcrab on it (Zombieland dictates that Double-Tapping is recommended in these situations). Smash the cabinet blocking the doorway.

The next area has some Poison headcrabs. Take them out, then use the switch to deactivate the electric fence. Return to the electric fence (there will be many Poisonous Headcrabs on the way back), climb up the ladders and onto the catwalks. Jump over to the roof and have another talk with the bald guy.

Hop onto the planks of wood towards the window. Hop through the window and toss a grenade down below to take care of most of the Zombies in this room (or use the Gas Can). Jump down and break the pieces of wood.

Outside, Gordon should be seeing a lever and a suspended car, as well as a swarm of Zombies headed towards his direction! Use the lever to bring down the car onto the Zombies. Search this area for Zombies. There's another car on strings that's initially on the ground. Use the lever to bring it up. At this moment, jump onto the car as it's being levitated (from here, he can hop to the other side of the steel fence, leading to Lambda 20). Jump on the plank and talk with Father Grigori, the bald man. Jump through the window.

Open the door and whack the Fast Headcrab with the Crowbar. Walk up the stairs and go through the door to the right. Father Grigori's in the building on the other side of the street. Secure this room. Climb over the window and kill all the Zombies on the rooftops. Shoot the explosive barrels to make quick work of the undead down below. Once all the enemies below are dispatched, hop down to the roads and head straight ahead to the ladder. Climb it, navigate across the planks, and see Father Grigori brawl out some Zombies. Kill the Headcrab inside the left rooftop and gather the supplies inside (Lambda 21). Go back onto the planks and enter the window of the other rooftop. Use the nearby sawblades to cut through the swarm of Zombies coming up the stairs. Head downstairs and walk through the building.

Step outdoors and hear some screams. It seems that werewolves aren't the only creatures that howl in the night. Kill the Fast Zombie that attempts to cut Gordon. Head into the windowed building and kill the Zombies behind the boxes. Walk up the stairs, dispatching the Zombie, and open the door to the right. Dispatch the two Zombies here, and kill the Zombie that breaks through on this floor. Head up to the highest floor, open the door, and meet up with the bald priest once again.

He's impressed with Gordon's work in Ravenholm, and gives him a SPAS-12 Gauge. Use it against the Fast Zombies that are now climbing up the pipes. Jump to the water tower and climb the ladder. Open the door and activate the elevator. While the elevator is ascending, fend off the Fast Zombies. Once the elevator is ready, hop on and descend. A Poison Zombie will appear outside the elevator below, so be ready to shoot at it. Once it is dead, jump on the car and run over the plank to reach the other side of the fence. Head inside the building, collect the supplies, then head back out, turn right, and move forward.

More Fast Zombies will jump down from the rooftops. Move towards the blade machine (this one's busted), and then head towards the lighted alley. This leads to a control tower. Use the switch on the balcony. Go back to the blade machine and then turn right and climb the boxes. Gordon must now make his way to the rooftops. Once Gordon's at one of the rooftops, run on top of the planks towards the rooftops at the other side. Father Grigori will give Gordon another helping hand, but it seems Gordon's not in the right place. Jump across the catwalks and into the window. Dispatch the Zombies in this building with the Sawblades.

The area downward leads back to where Gordon came from (that seems to explain this whole shaggy-dog route). Throw a Grenade up the ladder to flush out those Headcrabs in the attic. Head outside. Drop down and navigate towards the door near the light above. While doing this, be sure to kill all the Zombies here. Search the building for supplies and then climb the ladder. and Gordon will find himself on (another) rooftop (be sure to bring any available extra ammunition before going on top).

Grigori's nearby; he'll start sending the lift. Meanwhile, Gordon must fend off the Fast Zombies that will climb the pipes. Use the Shotgun to take them down. Alternatively, if Gordon's savvy enough, he can drop down on the catwalk where he entered this building. He can shut the door, preventing any Zombies from entering (very handy for that Zombie Chopper Achievement!). The priest will notify Gordon once the lift is ready. Use the switch, then hop onto the lift to meet up with Grigori face to face.

Collect the supplies on the table, and follow Grigori. Gordon & Grigori will be fighting in the graveyard, so keep an eye out for Zombies. Be sure to watch the back flank too. They'll come across a concrete floor, and its borders are flammable! Be careful in this area. Once the place goes up in flames, stay with Grigori on the stones. Gordon will come by a fence. Grigori will let him pass, but Grigori himself stays in the graveyard, fending off endless waves of Zombies. Gordon must now trudge through the mines.

Look down below. It's quite a fall, so Gordon will have to jump down onto the support planks in order to make it down safely (each floor of support will have a bend on it, this is where Gordon should jump down). Jump down onto one of the catwalks, and kill the Headcrabs from above. Once all the Headcrabs are deceased, look for a fence. On the catwalk, hop over the fence. Jump down into the water and then surface for air in the next area (avoid the Barnacles as well). Once Gordon has replenished his breath, crouch through the holes in the "X" and then surface again. Head to the mine cart and activate it. It has a sawblade that will cut Zombies in half, and will automatically zoom back and forth on the track. Use it to deal with the Zombies as Gordon walks up the tracks (be sure to avoid the cart). At the end of the mines, head towards the light!

Gordon may be out of Ravenholm, but that isn't the end of this chapter! Nearby are some crates containing lots of Shotgun Shells and Revolver Bullets (Lambda 21). Kill the Headcrab and nab the shells.

Turn right and follow the tracks (a Fast Zombie is on the top of one of the train cars). Ahead is a Sniper. Wait for him to dispatch the Zombies, then lob a Grenade in his window (look for his laser to locate him). Another Sniper is ahead. Crouch under the car with the logs. The Sniper will make the logs fall onto the tracks; use them for cover. When close enough, flush him out!

The next set of train cars has some Combine Soldiers. These guys are more dangerous than the Civil Protection units. While they're fighting the Zombies, kill all the enemies, and grab a Combine Rifle.

At the end of the tracks is a hole where Gordon can see through to take a look at the G-Man. In the parking lot are many cars and Soldiers. Dispatch the Soldiers and head indoors (be sure to grab the Rifle Grenade). Help out the Rebels in the garage by taking out the Soldiers. Poor Winston had a bad day!

Follow Leon (the black guy) and listen to the dialogue. Eli's been kidnapped by the Combine, and Alyx has a plan to rescue him (looks like the reverse "Damsel in Distress" protocol). Talk with Alyx on the radio. There's a car with a Tau cannon ready for Gordon to take him to Nova Prospekt (where Eli's held) in order to make it across alive from the Antlions. Collect the Supplies in the room and move outside.

Like Water Hazard, it is essential that the Buggy stays with Gordon as much as possible. Also like Water Hazard, Gordon must stop at places in order to pass.

Head outside. Collect the Supplies and grab the wheel of the Buggy. The Crane will attempt to bring Gordon down to the sand, but instead it drops Gordon onto the sand up-side down! Use the Gravity Gun to knock it back on its wheels (after dispatching the Antlions) and hop in. Head towards the shores and from there, drive up the cliff and turbo across the gap to the left. Follow the road from there (after stopping by a small building that has supplies, for Lambda 22).

After the loading screen, don't follow the road. Instead, turn right off the road where there's a gap in the rails. Head towards the beach and towards the Thumper.

Check the building here for Lambda 23. The only way inside is through the basement hatch. Stack various objects to get to its first floor (and watch out for the Poisonous Headcrabs and Zombies inside!).

Drive through the wall-things and drive across the second portion of the beach. Head to a second thumper and check the buildings. There's a few Combine Soldiers here, so dispatch them while they're distracted by the Antlions. In the white building, search for a camera. N.L.O. is located across the ocean from here, and it looks like their leader is talking to the G-Man.

Drive across the beach once Gordon is finished here. Ignore the next building (it only contains Grenades, something rather plentiful) and drive across the shores towards N.L.O. Park the car at the gate, and head into the basement of the two-story house. Try destroying all the foolishly-placed Explosive Barrels here.

Colonel Cubbage, the guy that talked to the G-Man, is giving a lesson on "How to use Bazookas 101". He'll notice Gordon and will offer the weapon to him. Pick it up. A Gunship is approaching, so Gordon must take it out!

Be sure to spin the Rocket in a spiral to confuse the Gunship, then hit it. It will take at least 3 Rockets to bring it down. There are many Rockets littered all over the base, and the Rebels will be more than willing to give Gordon more. Once the Gunship is rubble, head back to Cubbage. It seems that the next outpost, the Bridge, is under Combine rule. It happens to be the only way towards Lighthouse Point, the next haven. Once done talking with Cubbage, head back to the car, and follow the road again, and then turn right to the valley.

Keep driving through the valley and under the bridge (but don't sink too far in the water). Park the car next to the Thumper near the dock. Climb the dock (there will also be some Combine forces here; dispatch them) and head towards the white building. Collect the Supplies, head up the ladder, and advance towards the base of the crane (take out the Soldier on the crane first). Climb the crane's ladder, and take control of the crane. Attach its magnet to the Buggy, then transfer it in front of the gate of the warehouse on the other side of the pier. Use the Magnet to bring down the bridge for access, and to kill the Combine Soldiers that come out of the warehouse.

Head to the warehouse on foot. There's another squad of Soldiers inside. At the other end of the warehouse is a mini building with a switch. Collect the supplies, throw the switch, then head out of the building through the door Gordon just opened (don't forget the Buggy). After heading out, turn right, and to the right is another open building. Drive in and break through the glass window. Follow the road and drive over the gap in the bridge. Another Gunship is now attacking Gordon, so advance across the road to find a cache of Rockets. Use the Rockets to take down the Gunship (and hope it doesn't land on the road!). Once this task is fulfilled, use the Gravity Gun to throw the cars off the road in order to pass through. There's a small stash of goodies in the white car off the road to the left (Lambda 24).

There's some Roller Mines dug in the road ahead (don't mistake them for Dog's (playing) balls). With the Gravity Gun, toss them into the water. Ahead is a building. Unless Gordon's short on ammunition, ignore it, and keep driving. It may house various supplies, but the Combine's genre-savvy enough to ambush him here while he's relishing in his newfound toys.

Further ahead is a barricade. Shoot the Barrels on the truck to get through. The road ahead is blocked by some cars. Toss the cars into the ocean. On the hill is a Crossbow and more ammunition. Use the Crossbow to nail the Soldier on the Billboard (literally). Drive the car on the road to the Combine Field. Gordon can't drive through unless he shuts down the source that powers this wall. There's an APC near the building that's attatched to the wall. Push it with the Gravity Gun to allow access via Buggy. There's more supplies in the houses, and more inside the lonely generator behind the fences (stack some boxes to get over the fence and acquire Lambda 25).

Keep driving on the road until the road ends at the village near the bridge. Park on the rails leading to the bridge, and search behind the rocks to locate Lambda 26.

Dispatch the squad of Combine Soldiers, and then head to the cliff. On the cliff is a Poison Zombie. Gun it down, and hop onto the cliffs. Head to the door leading to the underside of the bridge.

Walk up the stairs inside and walk on the catwalks. The safest way across the Bridge is across the catwalk fragments. The nearest non-catwalk area has a substructure with a Headcrab and supplies. To get to the next area, walk towards the left, on the catwalks, on the supports, towards the whole catwalk on the left. There's a ladder here. Climb down and collect the supplies here.

Some Combine Soldiers will appear on the next area. Launch a Rocket at them. Continue on the catwalk. The next part of it is broken, so when Gordon reaches the broken part, go back on the supports of the bridge. There's enough catwalk here for Gordon to safely reach the next "area". There are Headcrabs in this building (unless Gordon already disposed of them with a Rocket when fighting the Combine). The Catwalk on the right is the best way to get across to the other side of the bridge (it has a gap, but it's jumpable).

Head down the stairs and onto the pathway. Soldiers will ambush Gordon from the right. Shoot them down. In the next room, shoot the barrel to the left to bring some objects down on more Soldiers. Head back out (through where the Combine came in) and shoot the Sniper on the tower. Climb the ladder and make quick work of the next Combine squad. Head indoors, grab the supplies, go upstairs, and say "Hello" to a pair of Soldiers. Use the Gravity Gun to pull the plug. This will disable the Combine Wall in the room. The switch on the other side of the wall will disable the Combine Wall on the bridge, allowing access. Use the Charging Stations first, then flick the switch.

A Gunship will appear outside. Try to fall back to where Gordon first came in the undersides. Head outside. Shoot the Gunship with the 3 Rockets Gordon initially has. The plateau with the ladder has an infinite supply of Rockets Gordon can use to destroy the Gunship. Once the Gunship is destroyed, go back to the Buggy (the catwalks on the left and right sides are the safest way back).

After exiting the underside, there's an Antlion fighting a Zombie. Kill both of these fiends. There's another platoon of Soldiers in the village. Dispatch them, board the Buggy, and drive onto the tracks of the bridge (there's a ramp that will allow Gordon to sucessfully drive onto the bridge near the tunnel). As Gordon's driving, he'll hear a train whistle. While it's tempting to use the Turbo Boost to zoom past the train in time, it's incredibly difficult to pull off. Instead, head towards the rails in reverse, and when the whistle sounds, Turbo back! Get off the rail before the train comes! When it's gone, stroll across the rails without worry. Drive up the broken highway and into the tunnel.

The first section of Sand Traps is pretty much another section of "Highway 17". The next part involves the use of the Gravity Gun to get past a sea of sand, and the third is an assault on Nova Prospekt.

In this tunnel, Gordon will come across a barricade of cars. Fend off the Zombies with the Gauss Cannon and use the Gravity Gun to knock back the cars to get through. In the rooms to the right are some supplies and Headcrabs. Use the Grenades to flush out the Headcrabs.

On the road is a couple of cars blocking Gordon's path. Use the Gravity Gun to flip them away (or drive into them, pushing them away). Keep driving on the road. The building ahead of the turn in the road has more supplies, and more ambushes. Ahead is a Combine Outpost. Destroy all the Soldiers in there and collect the supplies.

Keep following the road. Drive up the grassy hill on the right to get past the tanker. A Dropship will drop off more Combine troops here. Head into the building to the left. There's two missing batteries that would open up the gate. One is on the broken bed. Another is underneath a bathtub outside. Once the batteries are in place, the gate will open. There's also another Lambda Cache on the roof of the main building's bathroom (Lambda 27). Drive through the Combine forces and head to the tunnel.

Jayelgee says:

"There's also a fourth battery located on a plank protruding from the platform located high up on the windmill. Shoot the projection a couple of times with your rocket launcher to knock the battery down from its perch."

Gordon finally made it to Lighthouse Point! The captain here wants Gordon to park his car in the nearby garage. Lighthouse Point is about to be under attack, so find cover from the Dropship that lands and wait until the Dropship leaves. Fend off the Combine forces in this area.There are more supplies in the buildings if needed. More Dropships will approach the base, so stay in cover until the Dropship leaves.

Soon, a Gunship will arrive! Head to the Lighthouse and locate a stache of Rockets. Head to the top of the Lighthouse and use the Bazooka to clip the Gunship's wings. A Medic will talk to Gordon and lead him to the exit. At the bottom of the Lighthouse, exit through the door and jump across the cliffs (after dispatching another Soldier first).

Approach the field of sand (but don't step on it). The man on the rocks warns Gordon about the dangers of touching the sand. His friend, Laszlo, moves on the sand, and gets killed by Antlions. Help his friend by launching an MP7 Grenade at the Antlions. Talk with the Man, then navigate on the rocks to advance without touching the sand. There's a big gap between two rocks, so use the planks nearby in order to step on the sand without angering the Antlions (Gordon can use this method all the way to get to the cliff if he wishes). Step on the tall rock and jump to the lower rock. Jump onto the big rock and run across the rock pathway.

Gordon will eventually come across some wooden planks that resemble a see-saw. Put an item on the closer end and use that in order to get on top of the higher rocky area. To the right is a building with some 357 ammo. Jump across the dock and collect the supplies inside. Below on the sand is a boat holding a crate that includes more 357 ammo. To get back, use the planks nearby in order to get to the ramped part of the rock. To the left is some more rocks leading to the right direction.

On the last rock is a LONG plank of wood. Place in between this rock and the rock to the left. Once Gordon's on the other rock, bring the long plank with him. This building has a lot of supplies, and even more on the ridges above it (stack things to get on top towards Lambda 28).

Head to the ramp leading to the sand and put the plank here. Gordon will now have enough room to jump to the next rock. Inside this room is a generator that will power up a Thumper in the midst of the sand ahead. Throw the plank to the Thumper and make a dash for it! Thanks to the Thumper, the Antlions will not dare to harm Gordon. Somewhere around here is a white square plank. Step on either of the planks and then dispatch the Antlions (peferrably with the useless pistol). Use the two planks to get to the cliff on the other side.

Before stepping on the sand on the other side (Gordon will HAVE to step on that field of sand), bring the Explosive Barrels from the previous side to the next side of the cliff. Step on the sand (yes, STEP). An Antlion Guard will be summoned from the sand! Use the Gravity Gun to throw the Barrels at the Antlion Guard. While doing this, run to the other end of the field of sand. A Machine Gunner behind a wall will provide some extra damage to the Guard. If Gordon happens to run out of Explosive Barrels, use whatever's available to take it down.

After the Antlion Guard dies, a Vortigaunt will open the door in the wall and will extract the Pheropods and hand it to Gordon. Follow the Vortigaunt through the camp to another fortified wall. The Vortigaunt will lead Gordon to a sandy field. He'll train Gordon on the basics of Pheropods (aka, Bugbait). Once the training session is completed, go through the gate the Vort had opened, and trek through the valley.

More friendly Antlions will come by. Head outside onto the beach and turn right. There's a Thumper here. Deactivate it by climbing its ladder and pressing the button. Do the same for the next Thumper. Ahead is a bunker. Throw some Bugbait at the Bunker to make the Antlions flush out the soldiers there. Disable the next Thumper and secure the bunker to the left. Inside the bunker is a mounted gun. Use it on the Combine on the beach.

Advance across the beach. There are more bunkers on the top of the cliffs. Avoid the gunfire by staying close to the shores and behind the rocks. There's more Combine Soldiers here, so dispatch them with either Antlions or lead. To the left is an entryway to the bunkers and to the cliffs. Clear out the bunkers.

To the right after climbing the ramp is the insides of some ruins. That's the way to advance. There will be some Manhacks scratching around in this area, so use the Gravity Gun to deal with this threat. There is also a squad of more Soldiers here. With the Antlions, annihilate this platoon. Navigate around the rubble and head on out.

Sneak up on the next bunker and clear it out. Ahead is a Dropship dropping more Combine marines. Send the Antlions towards the next bunker and advance far enough to send the dropship flying in retreat. Return back to the larger bunker and use the mounted gun to eliminate any remaining Combine forces. Advance to the smaller bunker near the cliff. Collect the supplies inside and then head to where the Dropship was stationed.

Walk near the edge of the cliffs and then jump across to the other side. There is a pair of Zombies lying down near the fire. Use the Gravity Gun to pull the planks of wood supporting a wooden platform above the Zombies to send the ramp down, perhaps crushing the Zombies. Run up the platform and climb the cliffs, keeping an eye out for enemies above.

Gordon must now locate a sewer tunnel on the highest cliff. A Fast Zombie pops out of the tunnel! After killing it, head through the tunnel after the Antlions make quick work of the Combine on the catwalks above.

Trudge through the sewers and then Gordon finds himself in a shallow pool. Use the Crossbow to nail one of the Combine guards on the tower. Send the Antlions to battle after climbing up the ladder to get out of the pool. There are some supplies at the bottom of the towers.

Go up the stairs to the main level. Kill the Combine near the dumpsters. Head forward and lob a grenade into the small room to the left through the window. After the explosion, secure the supplies in the room (and use the charging Stations. The door is straight across). Not only one, but TWO Gunships will be up in the sky! Utilize as much cover as possible when taking down these two planes! There's a cache of Rockets a few stairs up. There are more Combine in another watchroom on the highest level. Take cover in there when taking down the Gunships.

Once the Gunships are now just a bad memory, head into a hole where there's a fire. Turn a valve on a pipe to extinguish this fire. Do the same for the next series of flame. Advance through the door.

Here is where things get hard. Gordon will have to utilize the strength of the Antlions to get through the Combine guards.

Open the door. Go down the stairs and search for the illuminated room on this floor. Go through the hole (after killing the Headcrab in it) to get to a security booth, containing some dead Combine guards. Exit the booth and Gordon will find a Turret shooting at Antlions beyond some jail bars. Use the Gravity Gun to punt the Turret. Head up the stairwell and crawl over (yes, over) the bent fence. There are more Turrets behind more jail bars. Send them flying.

Head towards the chair in the hallway and enter the next security booth. Examine the surveilance system (for a peek at the G-Man and a battle) and use the Charging Stations. Head to the end of this hallway. Climb the stairwell and turn left. There is a pair of Turrets. Knock them over and go through the door.

This room is flooded. Look up and kill any Barnacles in this region. Swim to the other side of the room, and go up the stairs. Follow the path and through the door. Climb the pile of rubble, and get ambushed by some Fast Headcrabs from above. After dispatching these parasites, go through the double-doors.

Fall to the second floor and go through the gate on the other side. Climb up the stairs and dodge the Turret fire. There's a bunch of supplies behind the locked door. Smash the planks to get Lambda 29. Topple the Turrets and turn around. Go through this corridor.

Kill the Headcrab hiding in the boxes and get to the end of the corridor. Here, jump down. Gordon must fight another Antlion Guard (he isn't fooled by Gordon's Bugbait!). Throw the nearby objects at the big Antlion, or use some heavy weapons. After defeating this boss, head to the showers area. There's a door that's blocked by a barricade. Use a Grenade to break the barricade. Go through. There's a toilet here (hint hint).

Ahead are some mean Combine Guards. Send the Antlions to battle. There are some Turrets at the opposite end of the room, and there are a few Manhacks present. Another Turret is located behind the gate, so avoid the open! Once all the baddies in this room are eliminated, another gate (leading to some jail cells) will open. Eliminate the enemies in this area. There is a Combine Wall charged by a plug on the other side. Pull it. Get into the booth, grab the revolver, and head upstairs. In the bunker, there's a switch underneath the windows. Press it to unlock the first gate mentioned in this paragraph. There's also a bunch of goods in one of the cells on the second floor (Lambda 30).

Go through the aforementioned gate. Smack the Turret behind the tables. To the left is a Combine Wall protecting the Combine forces. Get into the vent and jam a bucket or a brick in the fan, causing it to bust. Go through the harmless fan and exit through the vent. Eliminate all Combine resistance and pull the plug from the outlet, deactivating the Combine Wall.

Go up the stairs and hear Breen lecturing the Guards about Gordon, and their incompetence. There are many tripmines in this area, so watch out for red lasers. Turn right into the hallway. Ahead is another pair of Turrets. After knocking them to the floor, go up the stairs.

Destroy the Manhacks and get to the Machine Gun Emplacement and then go up the stairs. Dispatch the Combine platoon on this floor. There's another group of enemies on the other side of the floor, so go there and dispatch them.

On the rail-free catwalk, turn left and detonate the tripmine. Ahead in the next corridor is another bunch of guards hiding behind the barricades. After killing them, proceed and get spotted by the soldiers in the bunker. Get to the bunker by crossing another catwalk and turn left (after taking care of the tripmine). Avoid the Turret in the closet and eliminate the Soldiers. Topple the Turret and examine the screen. Gordon will have his first look at Combine Elites. Activate the switch. This will open a gate leading to the next area. Destroy the Soldiers that attempt to retake the bunker and advance through the recently opened gate.

Get inside the booth. Break the crate, use the First Aid Station, and check the screen. Get back out and continue through the corridor. There's another bundle of bad guys here. Take them out. To the left is a pair of Turrets. Knock them down. To the right is darkness with hidden tripmines. Try not to wander too far into that area. Go left again.

This is an open area. Use the Antlions to eliminate this Combine squad. The passages to the right lead to a room with a Poison Zombie and some Supplies. The upper floor in the previous room leads to the next area.

This hallway has two more Soldiers. To the right is another pair of Turrets. Throw a Grenade at them to knock them down. Gordon must head to the kitchen, which is on the right. Try to neutralize the tripmines in the hallways and topple the Turrets in the kitchen. Upon entering the kitchen, a gas pipe will be cut, and the room will become full of flammable gas. Go upstairs into another bunker. Collect the Supplies and make use of the Charging Stations.

There's a broken window that Gordon must jump through. When Gordon enters the cafeteria, the door will break, and an Antlion Guard will come busting through! Ignore the Combine Soldiers battling this beast and try to slay this monster as quickly as possible. After dealing with this creature, go to the wall opposite of where the Antlion broke through. In one of its corners is a gate blocked by some objects. Knock them back.

Go down the stairs and dispatch the Zombie. Go through the rubble. Look to the left for a firey entrance. There's a Headcrab in here. After bludgening it to death, go down the hole into the next chapter...

This area of Nova Prospekt is Antlion-Free (which means that the Pheropods are now useless), but Gordon will meet up with a more familiar ally: Alyx. She'll provide some help along the journey.

Keep heading down the rubble, and then run towards the tracks. Alyx is in a firefight. Go down underneath the rails and see a body plop down. Head to the gate after Alyx is done talking. She'll hop down and open the gate. Follow her into the elevator.

It looks like Nova Prospekt isn't really a defunct jail anymore (well, it is, but it's more than just a jail). After the elevator reaches its destination, help Alyx take out the Guards in this area. Follow Alyx again. She'll get Eli transported to another room for some chit-chat. Follow her, taking out numerous Combine along the way. Follow her into the small room and listen to the conversation between Alyx and Eli. Now it's time to find Judith.

Alyx will open up a door for Gordon to go through. Enter the corridor. On the left is a door to a room with Headcrabs and Supplies. Break through the boxes in the corridor and open the door on the other side. Soon enough, Alyx will hack into the surveilance system. She'll open the gate. Take a look above the vending machine (for Lambda 31).

The next gate will not open. Instead, go to the office. Break some items to reveal a vent in the wall. Crawl through the vent (and knock the Headcrabs dead). At the end of the vent, throw a Grenade to detonate the Tripmines in the room. Kill the Fast Headcrabs in the room if there's any left. Nab the Supply Crate and head to the gate. It will open. Get into the office, use the Grenade box, and take a look at the TV screen. Get ready to battle some Soldiers here!

Beyond the gate ahead is a pair of Turrets. Throw a Grenade at them to knock them to the floor. Ahead is a team of Combine Soldiers attempting to catch Gordon by surprise. Shoot them. Gordon will come across a Combine Wall. To deactivate it, Gordon must throw a Grenade into the lighted room to pull the plug.

Beyond the corner is a Turret. Knock it down before it notices Gordon! Ahead are two more Turrets. Toss a Grenade at them, and nab the Crate the Turrets were protecting.

Enter the Bunker ahead and kill the pair of Soldiers here. Alyx will allow Gordon to set up a pair of Turrets. Before using the Turrets though, use the First Aid Station and barricade the stairs, then set up the Turrets at the top of the stairs. Gordon must hold this position until Alyx gets here.

Combine Soldiers will attack the fort left and right. Some may even try to take out Gordon from the upper rails! Also, Manhacks will try to slice Gordon. Keep the Turrets intact. When all enemies are destroyed, Alyx will arrive.

Examine the security system with Alyx. It seems that Judith is really a double- crosser. Alyx will then deactivate the Combine Wall. Go through what used to be the wall and turn left.

Break the barricades and go through the door, then down the stairwell. The room below is full of Headcrabs, so lob a Grenade in there to flush them out. Go through the next door. The next room is flooded. Find some blue barrels. Place them at the other side in order to jump up there. There's some Revolver Ammo in this area. Use the Gravity Gun to take it.

The next area has four Zombies. Take them out. There's some very needy supplies in the room with electricity. Go up the stairwell. Head up to the second floor and nab the goodies on the second floor. Dispatch all the Soldiers guarding this cell. Jump down.

Gordon must defend himself against another wave of Combine Soldiers. Since the Soldiers will only actually arrive when the Turrets are set up, find the area with the Charging Stations. Use the Charging Stations, then find some Crates. Pick up the Crates and place them at the entrances to the area. Make sure the room is fully barricaded!

Whenever ready, set up the Turrets. The Combine forces have arrived! Make sure the Soldiers don't break the Crates or, more importantly, knock down those Turrets! This is where things get hard. Gordon's going to have to take a LOT of punishment from those pesky Soldiers!

Here's an alternate strategy by ZorkFox:

"In the second place where you have to set up turrets to ward offsoldiers, I found that setting a turret down IN a force field prevented it being knocked over by the soldiers. In fact, I frequently noticed two or three of them gathered around a turret, swatting at it with their weapons, trying to knock it down. The turrets can't shoot behind themselves, but this very neatly ties upmultiple soldiers, giving you a chance to come along behind and gun them down with whatever weapon you have handy: they seem to ignore theplayer completely because they're stuck in knock-down-turret mode!

I gave it another try last night while working on some achievements and found the placement of the turrets to be a little fiddly, but if you can get even one turret in the right place, it will distract soldiers. Unfortunately, it doesn't work in other turret battles, something to do with the fact that the force fields appear after the doors open, rather than being in place when you arrive as they are at all the other turret emplacement scenes."

Eventually, Alyx will come along (when all Soldiers are dead, unfortunatley). She'll open the gate. Be sure to use the Charging Stations before proceeding. Follow her downstairs and through the door.

The corridor will become pitch-black when Gordon and Alyx go through the hall far enough. Flares will light up and a squad of Combine Soldiers attempt to ambush the duo! Try not to get overwhelmed by this platoon. Use cover whenever possible. Go up the stairs after the firefight.

Use the First Aid Station. Alyx will lock up Judith through the panel. Follow her to the Combine Gate. Soldiers will start popping from the Combine Wall, so get through the gate as soon as possible. Alyx will lock up the gate.

Listen to a heated debate between Alyx and Judith. Judith's got the Combine teleporter up, so the good guys can make an escape from Nova Prospekt. Head to the Charging Stations and use them. A bit of talking to Kleiner and a distraction later, and Judith escapes with Eli without Gordon or Alyx.

Looks like the teleporter needs to be reset. And it's going to take a while. Set up the Turrets across from the Combine Walls to pin down the bad guys, while far from the Walls to prevent them from being knocked over. The enemies will only arrive when all the Turrets are set.

Keep fighting off the incoming enemies, and take good care of the Turrets. When the teleporter is ready, join Alyx (perhaps bring a Turret along the way with the Gravity Gun). The sky is falling! The floor is swarming with Soldiers! The-

Gordon and Alyx appear in Kleiner's lab (the area with the teleporter back in "Red Letter Day". According to Kleiner, the city is in revolt against the Combine (apparently a week later). Barney needs Gordon's help. Check the area for Supplies and drop down the hole. To the city!

In this and the following chapter, Gordon must utilize the aid of the various Rebels in the city to fight against the Combine. Unlike the Antlions, they are not COMPLETLEY expendable and disposable, and are much better at combat than Antlions. Pheropods are not required to command the proud Citizens.

Head outside. There's a small Supply Box on the ridge to the right (Lambda 32). Go to the car and Dog will throw the car at some unlucky Combine Soldiers. He'll battle an APC and throw it at another platoon (meanwhile, fight them off until Dog gets his job done)! Head to the gate and Dog will open it for Gordon. Unfortunatley, Dog must deal with a Dropship, and he gets carried into the sky! Hop over the fence and into the building. Search for a TV to see the G-Man live (despite the fact that the TV is unplugged). Crawl over the rubble and into the hallway.

Step out and help the Rebel smash the Scanners. Head to the town square. Three Rebels are tearing down a Breencast. More are dropping supplies from a tower above. A nearby Combine Gate will open. Dispatch the two CPs with incredible ease.

Lift the plate and hop down the hole (BEFORE lifting every Hopper Mine below!). Lift every Hopper in the field. Head into the house and collect the Supplies. Watch out for Hoppers and head to the dumpster. Pick up the Rifles (or let the Rebels use them) and head to the street. The Strider's tearing up the place (fortunatley, it won't attack Gordon). Above the street are some Scanners dropping Hoppers onto the Streets. A CP is on a tower. Knock him off and take care of the Hoppers (and kill any surviving Headcrabs).

Advance to the other side of the street, then turn right. Throw a Hopper at the furniture blocking the alley. Walk through the alley and throw another Hopper at the CP in the window. The shack to the right has some Supplies and some spare Hoppers. Another CP will appear in another window. Below the window is a shack. Knock the plate off and crawl in the shack to get some explosives (Lambda 33). Another CP to the left is standing next to some Barrels at the stairs. Kill him. Go down the stairs.

Watch out for the Hopper to the right. Beyond the fence is a group of CPs and some Scanners dropping more Hoppers! Take out the Scanners before they drop the Hoppers and kill the CP squad. Search the shack for Supplies, then enter the doorway into the building.

At the top floor of this building is some Supplies and a few nasty Zombies! Back at the first floor is the exit to another street. More Scanners drop more Hoppers! Hop down into the crater and shoot the explosive barrel next to the Turrets through the glass. Ignore the meanacing Strider and head to the campfire. Get into the building through the alley door.

Throw a Grenade at the boxes. Collect the Supplies and head up the stairs. At the highest floor available, clear out any CPs hiding in all the rooms. Outside is another CP. Hop down the hole below. Hopefully, the Turrets below have already been neutralized. Use the First Aid Station, then assault the wall!

Get past the crater by going through the glass. Throw the Hoppers at the CPs behind the wall and order the Rebels to hold the line against the wall. Gordon should head left and into the building. Climb upstairs, then fall down the hole and then head outside (there will be CPs and Hoppers along the way). Take out the CP on the rooftop and then open the Combine Gate. Close it when all the Rebels have made it through.

Go up the stairs and into the next building. Dispatch the two CPs on this floor and use the Charging Station. Get to the stairwell. One floor up is a Turret. After knocking it down, go downstairs. At the bottom floor, go to the hallway. Kill the CPs occupying this area. Search the rooms for more CPs to kill. Go down the stairwell. This floor has another squad of CPs and some Manhacks. After destroying these baddies, go down the next flights of stairs and knock down the three Turrets. A Zombie is down below. The stairs lead to Lambda 34, where it holds a bunch of useless Pistol ammo behind a fence.

Head through the underpass. LOTS of Manhacks will come from above. Smash them all and then head to the collision. There's a pair of Combine Rifles in the rubble. The gate is locked from the other side. Climb up the rubble at the end of the accident and hop on top of the fencing. Break the lock.

More Manhacks will come slashing through the windows. Ahead is a CP garrison. Snipe the CPs with the Crossbow from afar (there's plenty of bolts for it here). Head to the right towards the campfire and some Health Kits (Lambda 35). The Rebel behind the rubble will clear it out. In the meantime, defend this position against the Combine reinforcements. Use the Machine Guns to pin down the Soldiers, and use the Gravity Gun to smash the Manhacks. Once the charge blows, hurry through the hole!

Unfortunatley, Gordon must now cross a biohazard. Crawl through the hole leading to the radioactive subway. Smash the crates. To get through this lake of ooze to the other side, Gordon must locate a wooden wheel. Use the submerged vehicles and other objects with the Gravity Gun to cross through the goop (beware of Zombies that awake from in the waste). Once Gordon is on the other side, look left and crawl up the pipe. Break the vent and head back to where the Rebels are. Open the door and let them through. Go up the stairs.

Kill the Headcrabs coming out of the rocket. Talk to the Rebel behind the fence. Go up the stairs and kill the Headcrab. Break the planks of wood blocking the doorway. There are some Combine Soldiers fighting through the window (feel free to waste a few Pistol bullets at them). Go through the wall and up another set of stairs. Shoot the Combine next to the bridge through the window. Go right and see a battle between the Combine and some Rebels being mauled by a Strider.

Drop down the crater and nab the Crates. Head outside. See the wooden bridge on the rooftops get shot down. Kill the Combine on the roof, and the Rebel will open the door to the next apartment. Save the Rebel being chased by the Combine on the stairwell, and he/she'll get a Shotgun! Clear the Combine forces out of the stairwell and go up as far as possible. Then drop down the hole (so many).

Whack the Combine below to death. Before crossing the bridge, search the floor for Supplies. Kill the Combine on Gordon's side of the bridge and cross it. Nab the Supplies the Rebel has been guarding. Go into the dark area and search the rooms to the left for a MP7 Grenade. Head to the stairwell with a Headcrab Rocket in it. Go up and eliminate the Headcrabs and the Fast Zombie in this ruined area. Drop down the hole. Feed the Firey Fast Zombie that pops up the next hole some buckshot. Drop down and blow the Zombie away.

The room with the door leading outside has a pair of Fast Headcrabs and lots of boxes. Go outside and watch out for the Hoppers. There's Combine on the rooftops and in the courtyard. Enter the building to the left. Go up the rubble. If Gordon's lost a lot of Rebels in combat, there will be more to back him up at the second floor. Bring down the bridge and cross to the next building (once the area is free of Combine).

Collect the Supplies on this floor, drop down the hole, and clear out the Combine. Go up the stairs and take out the two Barnacles. Drop down the hole. Go to the wall opposite of the hole with the planks in them and kill the firey Fast Zombie. Kill the Combine on this floor and drop a Grenade down the hole to flush out all the Zombies and Soldiers. Drop through the hole. Go down the stairs. Look for the Lambda Symbol. There are some Supplies in the crates behind the fence to the left (Lambda 36). Go up the stairs in the building.

Head through the hallways to find a hole in the floor in one of the rooms. Drop a Grenade down the hole to destroy the Zombies and the Turrets. Drop down and use the Charging Stations. Alyx will break the door. Eliminate all Combine forces on this floor after she's done talking. Use the Charging Stations in the stairwell and then go down the Stairs. Take out the Combine Soldiers in the next room.

Alyx will discuss the plan. Our heroes will get to the courtyard and take out the CPs guarding the Generator. Alyx will then hack into the Generator terminal, and once she's done taking off the shields, Gordon must blast the Generator's power supply with the Gravity Gun. If Gordon's low on Rebels, more Rebels will join Gordon's cause.

Go through the hallways and head outside. Snipe the CP on the tower. Assassinate the other CPs guarding the generator. Collect the supplies near the fountain and use the Charging Stations next to the terminal. The Combine Forces will attack through the Combine Walls. A CP will also appear on the balcony. Use the Hoppers as either traps, or instant explosives. Once Alyx gives the word, use the Gravity Gun on the ball. Then hurry through the gate!

Alyx tries to find a way to get across the canal. Unfortunately, in the process of doing so, she gets kidnapped by the Combine. Go down the Canal (any surviving Rebels will not want to follow) and go through the alley leading to the underworld...

Open the gate and land on the crates. In the hallway ahead, destroy all of the Manhacks hacking through. Turn around and remove a barrel holding up the panel. Climb up the panel and onto the pipes. Head to the vent. YIKES! More Manhacks will smash through the window to the left! Smash them and crawl through the vent. Jump down and smash the Manhacks coming from the left and from the windows. The path to the right leads to a chasm with Combine forces on the top floor and a Zombie below. Drop down three floors and go through the lighted hallway (there's also a small alcove in the ravine that leads to Lambda 37). Go through the single door and kill the Poison Headcrab. Through the window, use the Gravity Gun to pull the bar off the double-doors. Go through the aforementioned doors.

Kill the Combine Soldier ahead and watch the battle between a pair of Soldiers and a horde of Zombies take place in the sewer. While this is going on, get to the hallway ahead and kill all the Headcrabs and Barnacles. Get to the other side and watch the unlucky Soldier get devoured by the Barnacle. Go up the stairs and throw a grenade at the wooden plank. This will kill the Poison Headcrabs attempting to ambush Gordon. Collect the Supplies, then go back and drop down into the sewer. By now, the only enemies in the sewer is the Soldier, or some Zombies.

Head through the hallways and kill the Headcrabs. Before going up the ladder to the right, advance forward. There's a hole in the wall containing lots of Supplies (Lambda 38). There's also a Poison Zombie in this area. The dead end leads to more Supplies (Lambda 39). Head back to the ladder.

Throw a Grenade up the ladder and climb it. Head to the canal. Turn left and kill the Headcrabs. Then climb over the rubble. Walk up the ramps and walk across the catwalk. Thanks to a Grenade and the Barrels, the catwalk will break. Walk across the slanted area to get to where the catwalk was leading to (be sure to kill the Barnacle above the gate door).

Enter the shack and use the switch to get the platform moving to Gordon's side. Collect the Supplies and use the Charging Stations. Kill the pesky Soldiers above. When the platform has reached Gordon's side, flip the switch again and hop on the platform. Watch out for more Combine from above. Once the platform has reached its destination, head to the tower and climb the ladder.

Walk across the beams that hangs the platform. Cross it (kill the Combine attempting to flip the switch in the shack). Follow the beams to the catwalk. Climb the ladder and take out the ambushing Combine forces. Hop down on the balcony where the regular Soldiers were attacking (don't forget to check behind the red building for Lambda 40!). Lift the Hopper and follow the hallways (taking down any Combine Machines in the way).

Here's where things REALLY get tense. The first half involves an adventure with Barney on an attack to one of the Combine's main structures. Then it's a crazy fight in the city!

Talk with the Rebel. Remember the Snipers from the train station near Ravenholm? They're back in City 17, and they're dominating the streets! If Gordon preserved his Rockets all the way from when he entered Nova Prospekt, he should be able to take out the Snipers with ease! The first one is directly across this lane. Launch an explosive at him. Another one is around the corner to the right. Enter the large building through the door on this street.

This place is crawling with Headcrabs and Zombies! Neutralize them all on this floor. Head down to the flooded basement. Talk with the wounded Rebel, and then kill the Zombies that emerge from the water! Go up the stairwell (killing the Fast Zombies) and watch the Sniper kill all the Zombies in the outdoor floor. Toss a Grenade in the Sniper's window to the left. Talk with Barney. He's on the rooftop. Go up the stairs and flush out the two Snipers pinning him down (ignore the Poison Headcrabs). Head back down one floor and exit by heading out through the ruined wall. Barney will open the gate. Destroy the Scanners dropping Hoppers. Head into the building and kill the Poison Headcrabs.

Combine forces will bust through the door ahead. Throw a Grenade at them to kill them and knock down the Turret. Grab the Supplies and go up the stairs. Look through the window. Gordon can launch a Rocket at the Combine squad in front of the building for fun. Barney will open the door and Gordon will be immediatley spotted by a pesky camera! Go down the stairs, knocking down the Turret and defusing the Hopper on the way. Head outdoors.

The Suppression device is bombing the street! Sprint across the street, avoiding the pothole, and enter the door to the left. Kill the Combine here and use the First Aid Station. Exit through the door to the left and make a run for the small building in the middle of the yard. Collect the ammo and head to the building on the other side. Here's a POW camp. If Gordon's lost enough Rebels, more will join his cause. Free them and collect the weapons.

In front of the nexus, lots of Soldiers will bust through the entrance! Take them out and head to the Combine wall. Deactivate it by using the Gravity Gun on the plug. Use the First Aid Station and advance into the base.

There's a Ground Turret guarding the door. Unlike the other Turrets, these ones emerge from the floor and activate only when someone has passed through the laser grid. Lob a Grenade into the Turret. In the foyer, neutralize the Combine coming from the Combine Wall. Pass the Grid and take out the two Ground Turrets. Kill the two Combine Soldiers. Bring up the Shotgun up the stairs.

Free the Prisoners. Collect the Weapons and let one of the Prisoners get the Shotgun. Disable the two Ground Turrets guarding the first Generator. Once the two guns are destroyed, go into the carpeted room and eliminate the first Generator. Collect the Supplies and use the Charging Stations. Head for the bridge. Cross it and disable the Ground Turret protecting the Supplies. Meanwhile, a squad of Combine Soldiers will appear in the foyer. Battle them to the death.

Head into the room with many Hoppers and laser tripwires (the Rebels won't follow until Gordon deactivates the wires). Hop across the metal objects to avoid the lasers. There's a switch on the other side of the room. Press it to deactivate the security. Collect the Supplies next to the switch and regroup with the Rebels. The security room was guarding the second Generator. Blast it and fight the Combine squad! Head back to the foyer.

Now that some of the Combine Walls are disabled, Gordon and his friends can advance to the third and final Generator. Keep advancing through the hallways leading to an unfinished room. Nab the Supplies on the shelves and set up the Hoppers next to the doors. Dispatch the Combine coming from both directions. Disable the two Turrets ahead, and pull the plug on the last Generator!

Go back to the bottom floor of the foyer. Now that the power is out, the Combine Wall leading to the dark hallway is cooked! Kill the Combine forces in the hallway and neutralize the Hoppers. Nab the Supplies and let Barney open the gate. He'll stay here while Gordon goes to the roof. Go up the Stairwell.

Kill all the Combine in this area (including the guard on the top of the tower). Send the Rebels to some cover. Use the Bazooka to take down that Gunship (and do it quickly to save the Rebels' lives)! There's a Rocket Dispenser on the roof. Once the Gunship is down from the skies, the gate will open. Set up the Hoppers and kill the Combine coming from the Dropship. Activate the rooftop bridge and flush out the Combine on the other side. Drop down the stairwell.

Meet up with the Rebel. Since the suppressor is destroyed, the Rebels have the advantage (albeit having the Striders roaming the streets!). Go outside. Unload as many Rockets at the Strider as possible, then run to the other side of the courtyard! Go down the pothole and go through the tunnel. Avoid the Strider's legs and head to the building with the jail. Grab the Rocket Launchers and fire at the Striders! Head to the shallow building and nab the Supplies. Keep the Rebel safe and shoot down that Strider! Head to the rubble. Here, there's another Rocket Dispenser. Use the Rockets against another Strider! There's also a Combine garrison at the end of the street. Destroy the Combine forces there. Go down the stairs and nab the Supplies containing useless Pistol Ammo (the crappy kind by the way. For this reason, it's not really necessary to break these boxes other than obtaining Lambda 41).

Dispatch the Soldier at the far end of the street. Run across the Street as fast as possible, because a Strider will break through from behind! Head into the building to the left. Destroy the Scanners and Combine in the building and keep heading upward. On the damaged floor (with no roof), run around and the Strider will attack the floor, causing a plank to fall down. Go up the plank and cross the beams leading to the stairwell. The stairwell has a Rocket Dispenser. Take out the Strider before it can do any more harm. Break the crates and hop down the hole (Lambda 42).

Break the wooden planks and meet with the Rebel. Head outside. Avoid the Strider and head down under the roads. Kill all the Combine down here and nab any Supplies. Go up to the other side of the rubble on street level. Dash to the room with the glass. Flush out those Combine Elites and collect the Supplies in there (trust me, Gordon will need it). Go down the hole under the rubble blocking the street and into the next room with supplies. Keep going across the street to the rubble, and a Strider will bust through! Avoid its legs and go under.

Listen for the charge and back away as soon as it detonates. Kill the Combine here and surface back up into a messy battlefield! The Soldiers will attack Gordon from above. Gordon must go one floor up and kill all the Combine Soldiers in the area. A Strider will appear and wreck the place up. Go through the destroyed walls to the next area. Head into the big house, use the Charging Stations, and head to its highest floor. Use the Rocket Dispenser and take down all the Striders!

Walk across the beams leading to the horse statue. Dog will come bursting through. Try not to get in his way while he smashes the Combine. We're just next to the Citadel! Dog will open the gates and allow Gordon to get through. Dog releases the gate as Barney says some profanity. Go through the tunnel.

In this and the next chapter, Gordon's only weapon will be the Gravity Gun. However, thanks to a Combine Security Field mishap, it can now control biological objects (including unlucky Combine Soldiers). It also is more powerful, so Gordon can also lift massive terminals! Have fun!

Head down the rocks and hop onto the piston when it's high enough. Head through the tower and Gordon will eventually encounter some "lifts". Take the one farther away (the closer one will lead to a deadly beam!). Gordon will now go through a long and boring tour of the Citadel.

Eventually, he gets trapped in a Security Field, and it takes all of his weapons away! Well, almost all of his weapons. The Gravity Gun, by contrast, is juiced up and now glows teal. Go through the hallways and kill the Combine Soldiers with this new toy. Talk with Breen in person through the terminal.

Use the nearby Charging Station. Gordon's Suit level has a maximum value of 200. The Stations will also give Gordon health. Advance across the bridge and kill the Combine forces. There is also a single Scanner in the bridge. Destroy it with ease. Talk with Breen again, and drop down the rail leading to a Combine generator-thing. Corpses of Combine Soldiers can be placed here and will be disintegrated. Search for an elevator, and go up before more Combine grunts show up!

Kill the pair of Combine. Pull the Combine Ball in the Generator away to deactivate the Combine Wall. Use the Charging Station and meet with MORE Combine! Disable the next Wall and advance.

Activate the Elevator and use the Charging Station. It looks like Dr. Breen is starting to get agitated! Fight off the Combine forces (which includes Soldiers, Elites, Scanners, and Manhacks). Once the Elevator is ready, go up and fight off the Combine while the Elevator works. At the top of the Elevator, deactivate the Generator.

Take out the Soldiers to the left and move on. Find an exit out of this area with the generator. Kill the Combine Soldiers and talk with Dr. Breen again. Hop down into the chamber and kill the Strider with the Energy Balls. Breen's beginning to worry! Deactivate the Generator and hop through the wall.

Use the Charging Station and board the lift. Here we go again...

The final climatic chapter. After a meeting with Dr. Breen, Gordon must battle his way in the Citadel core and fight for his life!

Judith escorts Gordon to Breen's office. It looks like he has both the Vances with him. He also mentions a few abstract things, and starts to send the Vances into the Combine Portal. In a surprise twist, Judith betrays Breen and joins forces with good again. Breen attempts to use the stolen Gravity Gun against Gordon to make his escape. Go into the elevator with Alyx and chase Breen, talking to a Combine Advisor (more will be revealed in the later games). He escapes into another elevator. Grab the Gravity Gun and take a look outside. Meet the Citadel core! It needs to be destroyed to prevent Breen's escape! Use the Charging Station and go down the elevator for the battle of Gordon's lifetime!

Listen to Breen's chit-chat. Soon, a panel will open, and Gordon can begin his journey up to the core. Avoid the Soldiers and deactivate all three Combine Generators (they can hurt things inside them). Go up the platform and dispatch the goons. Head to the small platform, as it leads to the core's tower.

Use the Charging Station and go up another vertical platform. Kill the next batch of bad guys and go up the large platform moving along the wall. Gordon is now at the highest level of the Citadel. Launch an Energy Ball at the core (it's the glowing sphere in the tower). A pair of Gunships will attempt to stop Gordon. The Energy Balls can be used against the Gunships. Once Gordon hits the core once, the core will be protected by some shields. Throw the Balls at the shields to knock them down. Take one last shot at the core, and Breen will meet his mysterious demise.

The Citadel's going to blow! Hopefully, our heroes still have...

...time, Doctor Freeman? The G-Man re-appears in Gordon's midst to bring him back into a void for his work. Rather than offering him the illusion of free choice (and the allusion of the previous game's ending), the G-Man will simply do the chosing himself.

Gordon is back in the darkness with the G-Man, but not for long...