I think this is the first FPS I've sunk countless hours into, and unfortunately, I didn't have a ton of friends to play the multiplayer with, which most people will say is the best part. It's thanks to this game that FPS games got a chance to grow on consoles. Images of the game world are burnt into my mind, as I remember being impressed (and amused by the stupidity of) the enemy AI and the objective based gameplay that gave you something to aim for and do besides "shoot everybody in your way to the end". My brother and I spent so much time trying to figure out the objectives and wrestling with the cumbersome controls the game has - thankfully, the game is built around those controls so you can live with the lack of fast aiming when your enemies are taking time to shoot you with fancy animations and genuinely showing pain in reaction to being hit, which you just don't see in much shooters beyond mild flinching and death animations.