Update: The rumored BioShock 2 details making their way around the internet aren't factual, publisher 2K Games tells Shacknews.

"This rumor isn't true," stated 2K community manager Elizabeth Tobey. "Do not believe everything you read on the internet."

She added that only one aspect of the rumored details is accurate, and pointed to Game Informer's recent note, which indicates there is only one Big Sister.

Original: With the latest Game Informer issue off to subscribers, supposed details from the BioShock 2 cover story have hit the 2K Forum.

Taking place some seven years after the original, BioShock 2 apparently puts players in the role of private investigator Jack Abbott. The game kicks off as Jack chases the Big Sister that has kidnapped his friend's daughter, and makes his way to Rapture.

The shooter sequel will also supposedly feature two-player cooperative play. More alleged details follow below, but be warned that they contain potential spoilers:

• There's only one Big Sister, and Big Daddies do not return.
• Rapture is mostly flooded, and the game has underwater diving levels.
• A Zoo level features "spliced" animals, such as a rhinoceros.
• Spliced dogs and robots are among the new enemies.
• Those robots can be hacked to help players.
• There will be "epic boss battles," including a fight against a giant squid.
• At some point, Soviets invade Rapture, looking for the lucrative Adam energy. The Soviets are "much smarter" than other enemies, and will use plasmids.
• New plasmids include telepathy and the ability to slow time. By reading minds, players can discover keypad combination and enemy weaknesses.
• There will be challenge rooms, as well as a new health and revival system.

Developed by 2K Marin, BioShock 2: Sea of Dreams is slated to launch between August 1 and October 31, 2009. The game is "destined" for PC, PlayStation 3, and Xbox 360, though publisher 2K has yet to reveal what systems it will hit by October's end.