I finished BioShock for the third time the other night, and even knowing the story and the big plot twist, it has still lost none of its potency. I think that Rapture - the vast underwater city that is the setting of BioShock - is one of the greatest and most fully-realized environments created for a work of fiction. But I'm scratching my head at how Hartmann and 2K are already conceiving of five more games to offshoot from the original. Most fans of BioShock that I've spoken to have said that they'd like to see a prequel at some point: a game that shows us life in Rapture leading up to and taking place during the events of New Years Eve 1958, when the oceanic metropolis collapsed into the total chaos of civil war.
The first sequel, BioShock 2: Sea of Dreams, is due to be released this coming fall.