Bioshock is the type of experience I got into gaming in the first place for; immersive, entertaining, and way cool!
The reason for this, as for the reason for it's high marks in many players reviews, is the story. The story is very worthy of a big budget motion picture. As a shooter it brings some newness as well: new weapons, new powers, a new explanation for the powers, and it does so better than most. But again, it is the story that will keep you in front of your monitor or television as you try to figure this thing out. Beyond saying that this is an action/adventure in an elaborate city built on the bottom of the ocean I will give no spoilers. If you are on the fence about playing this game just trust me and the countless few who have given this underwater epic rave reviews.
Enjoy the telling and unfolding of the story, take some pictures, and be comforted knowing that a second sequel is on its' way.