BioShock has recently been released and is now available to be purchased on Steam. What is BioShock?

"BioShock is one of the most critically-acclaimed games in years, with a 97% average Metacritic rating. Players enter the game as a castaway in Rapture, an underwater utopia torn apart by civil war. Caught between powerful forces and hunted down by genetically modified "splicers" and deadly security systems, players have to come to grips with a deadly, mysterious world filled with powerful technology and fascinating characters. No encounter ever plays out the same and no two gamers will play BioShock the same way."

There is also a demo available for download.