An immersive underwater world sets this shooter apart.
As for the production value of the game itself, it is superb. The visuals are stunning, and added scripted detail further enhances the experience at every turn. The sound effects and voice acting are simply fantastic.
Gameplay is a pleasure in BioShock. The additional skills you discover are both useful and fun to wield. One aspect I found particularly surprising, and something that sets BioShock apart from other shooters is the pace of battle. The foes you encounter move extremely fast and keeping a steady hand is critically important. The ammo supply is limited, which behooves the player to restrain from blasting away blindly.
Story is the central strength of BioShock. The audio recordings and creepy Art Deco design lead the player down a very interesting and disturbing story line that benefits from quality writing and acting.
BioShock is probably the best new game I've played in 2007, but it does have some disappointments. For one, there is no multi-player support. For other shooters, multiplayer action accounts for a good part of the value of the game, and would've been a very good addition. As for other gripes, the variety of foes and weapons is a bit lacking.
All told, BioShock is an enjoyable diversion and a very well-polished title and is recommended for fans of single player story rich shooters.