Half-Life 2's AI is NOT basic, trust me. I was coming out of the mines section of the game (Shut up, this isn't a spoiler!) and there were combine snipers everywhere. I went to hide under a train, and the sniper was smart enough to shoot the barrels next to the train to flush me out. Wait! I'm not done typing! The AI actually work together to try and kill you, they don't just run around and shoot wildly like in SA. The combine (Or if there is more than one of the Xen chasing you) will actually move in formation and use cover (They even use each other as cover). The game is very balanced between prettyness, realism, and gameplay. You can interact in some way with almost everything around you. They spent a total of 6 years developing the game, with one of those just being for planning. The idea of the game is genious. On the other hand, you have GTA: SA. The gameplay in that piece of crap has been done sooo many times before that it's just not fun anymore. If they had released it last year, I might say different, because last year's games sucked. But with all of the games being released this year, I say that GTA: SA is crap. Crippity Crip CRAP.