I'm new to the series and got here via Portal. Now I want to catch up but I'm confused about what to buy. The correct order of the games was easy enough to Google. But what are the decision-making differences between Half-Life and Half-Life Source? I think one has better graphics, but one has mods, but mods mean good graphics (or Morrowind has spoiled me) and...I'm confused. And someone somewhere said that one has "better" gore than the other, which makes me wonder if maybe one version has settings or mods to turn the gore down. Is it true that the expansions are only available for one version? Do both versions handle 64-bit systems alright? Is one better about widescreen, and if so, does playing in widescreen mess up cinematic parts of the game that were designed for 4:3? (I try to Google this stuff, and just get people's silly arguments over how one random detail makes Source better or worse.) Going back to mods, are there ones you'd recommend using on a first and possibly only play-through? Graphics, annoyance-fixers, etc.. And then, which games/expansions/episodes are really about the multiplayer? I saw that one Half-Life title is based around co-op, forget which. Is it ONLY co-op, as in, I shouldn't touch it since I never do multiplayer? I'm pretty much in it for the story. Are there any expansions (etc.) I can skip because they aren't part of the plot? Any other general (and spoiler-free) advice is welcome, too. Thanks for any answers you can give.