What a nice game. Bioshock succeeds in being a cool and well-thought out vision of retro sci-fi, and an effective horror game with nasty psychological twists.
If you have tried Bioshock, you'll instantly sense that this is a game of the highest quality; Everything is polished and intelligently designed. The graphics is overwhelmingly detailed and quite unique and the sound design is eerie and menacing. The AIs of the enemies also work perfectly. The Splices wander around aimlessly, talk errantly with themselves, and launch savage attacks, which fits the story background of the game perfectly. An important point in good game design: turn eventual weaknesses of your game into strengths through the story.
The game is quite long, and it sometimes seems like an grueling death march, but only because you are sucked into the dark, evil atmosphere of Rapture. The game isn't really hard, as the Vita-chambers (= respawn points) ensure that you always will be able to continue the game. I didn't really die a lot of times, just by playing a little bit carefully, which seems reasonable in the generally unpleasant surroundings provided by the game.
But a little warning to avoid disappointment - the end sequence for completing the game is ridiculously short and uninteresting.