Set before the collapse of Rapture
It's inevitable that they'll be a sequel to Bioshock, one of 2007's most atmospheric and original shooters, sooner or later - which is exciting enough in itself - but it's also been suggested that Irrational Games will not be creating a straightforward sequel and will instead develop a prequel, set before the destruction of the hidden city of Rapture.The rumour comes from Czech website, Hrej.cz who claim that Bioshock 2 is currently under development at the 2K Games' Czech studio (the team currently working on Mafia II) and will be released in 2009.
According to the story of Bioshock, Rapture was constructed as an ideal society for a hand-picked group of scientists, artists and industrialists, but collapsed under the weight of its own idealism. The thought of exploring the neon-lit metropolis before it was destroyed is an exciting one and if Irrational put as much effort into the visual aspect of the game as they did with the stunning looking Bioshock, exploring Rapture is going to be a truly spectacular experience.
2K Games has declined to comment on the rumour.
Source :: Hrej.Cz via Xbox 360 Fanboy