A different kind of shooter.
In Bioshock you play as a nameless man, who crash lands in the ocean somewhere during 1960´s and swims to a some distant island. For some reason there´s an elevator and since you have nowhere else to go you take it. This is Rapture: an underwater utopia, in which something has gone terribly wrong. It´s your job to find out what´s going on and get out alive in the process. Your choices have effects on how the game will end. There´s only a few cutscenes during the whole experience, so the bulk of the game is told through character´s eyes just like in Half-Life 2.
Graphics are absolutely brilliant and Rapture has a distinctive 1960´s feel written all over it. Environments are alive and detailed with appropriate colors. If possible the sound is even better. There´s a network of sound effects from dripping water to candy machines making beeping sounds. Voice acting is also excellent so overall the audiovisual presentation of Bioshock is as good as you can ask for.
Gameplay is somewhat free, but in the end you´ll find yourself moving forward in predetermined path and you have little or no reason to take detours from it. Exploring is a big part of Bioshock in the beginning, but towards the end the shooting takes the front stage and this is not a good thing. Your enemies, which are called splicers, spawn behind you from nowhere occasionally and their movement is weird: they don´t look like people, but maybe that was the goal in mind for the designers. Usually splicers are just irritating, because they interrupt your exploring. In Bioshock shooting is not very fun or satisfying.
Your character can upgrade his abilities in many different ways and this keeps the game fresh from beginning to end: you always have something new to play with.
Subtitles come in a different pace when comparing the sound you hear so this sometimes makes it a little hard to follow the dialog.
Save system is just the way it should be: there are some checkpoints, but you can still save anywhere anytime. You can also change the difficulty setting anytime you wish so Bioshock is not about challenge: it´s about taking a journey to Rapture. A nice feature is that you don´t have to kill everyone you meet during the game.
There is no multiplayer what so ever, but you don´t need it, since this is a story driven game and not a very good shooter.
If you like games like Metroid Prime, Thief and Doom 3: this is a game for you. Bioshock is in a word different.