This games singleplayer stands up on its own, but the best part of this game is the coop multiplayer. Its pretty cool killing about a hundred aliens at once with allies at you side. If you need a coop game, this is what you want.
When I first saw fallout 2, I didn't like the look of the isometric interface. But when I bought it after reading some reviews, the game blew my mind. It has totally non-linear game play, meaning you can do several things to complete a quest. Say for example, you have to break somebody out of a prison? You can either negotiate with the guards, sneak in and break them out, or kill all the guards and release him. I can recommend this game to anybody in need of a Good RPG.
