Okay, I've jumped on the opportunity to create this thread before anyone else Post your theories on anything HL2 related here, ya? :cheese: I'll start - I reckon there could be a fair few sides, The Combine, the New Aliens, the Old Aliens (Headcrabs etc), and maybe another side of the Old Aliens (remember in HL1? The Bullsquid, which will apparantly be back in HL2, hated all the other Aliens), and then of course, Gordon's side, whatever that may be. Soo.. City 17, a nice peacefull place, untill The Combine come in and take over, with their ground troops (who I believe are a mix between Robotic and Organic matter) and their Mechanicals (Striders, maybe?). I would say that these guys are in league with some of the Aliens, such as the Ant-Lions, but as seen in the Bug-Bait video, that is probably not so, although you could say that the Ant-Lions were stupid enough to be tricked into attacking the Combine Soliders, and they shot back to defend themselves against the crazed beasts, but then theres the huge freaky Ant-Lion at the end, who seems intent on killing everything? Anyway, they're slowly taking over City 17 using the Black/Grey Tower thingies, which I think is a splitting image of the Zerg's Creep in Starcraft, or the Undeads' Creep thingy in Warcraft. Heres where my theory goes abit weird - The Combine are not only doing this to earth, but to other dimensions too, such as Xen, since they don't look pretty earth like to me, I figure they are from a different dimension/planet altogether. Somehow, Earth/City 17 (which may be the last remainly place on earth not yet taken over by the Combine, although where the G-Man and his mates are hanging out is beyond me), becomes a massive portal where aliens from all dimensions are pulled into it. This would explain why the sides appear to be against each other, some of the aliens (such as the Ant-Lions) may simply be scared, and thus attack anything that moves, others, such as the Headcrabs, latch on to any civilians/combine they find hanging around and populate the City with Zombies. Some of the smarter aliens, however, team up with the earthlings, aka - Gordon and his friends. Hmm, so where does Gordon and Mr. G-Man fit into my theory? Uhh, well im not so sure, really... Well, go on, post your theories guys!