Number 33
Half-Life 2
This is one of the few games that I have trouble describing, at least in terms of what makes it so fantastic. It is certainly true that the action is well-integrated into the narrative, and that walking through any part of this game gives the sense of being removed and thrust into an alien world that you may have known once, long ago, before a corrupting hand shaped it into something horrible. It is a game that knows how to press the buttons of the brain, to illicit fear and courage and a sense of strangeness as well as any game, or even any piece of media.
Is it enough to sya that the game feels real, even though you have a gun that manipulates gravity? I think so. I think that sums up everything very nicely.