the first trailer for bioshock has been leaked onto the internet via youtube. although this is probably not what the creators wanted it has certianly drumed up alot of interest. [ame=https://www.youtube.com/watch?v=Rzf18bZCPCI]YouTube - Bioshock 2: Sea of Dreams (PS3 Teaser)[/ame] if you want to see some of the speculation click on this link What secrets does the BioShock 2 trailer hold? | GamesRadar
I did hope Bioshock 2 was going to be a prequel as it would've been interesting to see how Rapture Spoiler collapsed after the introduction of Adam, the little sisters and Atlas but the trailer seems to imply it's to be set after the events of the first game.