At first I thought I was going to be bored with Bioshock since the mechanisms of the game were virtually identical to System Shock II, which I'd played all the way through. But the story was so compelling and the immersive feel of the collapsing underwater Randian-Utopia city (say that five times fast) was so complete that I wasn't bored for a second.
The details are what really made the game for me, like the whirr-huff-click sounds of the various electro-mechanical and pneumatic machines and the fact that the 'turret guns' are mounted on swivel office chairs. And I found that learning the history of Rapture largely through it's citizens' discarded "Audio Diaries" to be oddly engrossing.
Oh, and it was a lot easier than SS2, which, for me, was a bonus.
FuzzyCo grade: A