Since it’s closure back on August 22, Games for Windows Live has prevented users from purchasing any new content even though the functionality remains in place for people to use the service. You may be able to see how this was a problem for BioShock 2 which was previously a Games for Windows Live only release, locking people out from purchasing really anything related to the title. 2K Games saw this and decided to make good to anyone affected by the GFWL closure.
With the game now being officially up on Steam, 2K also took the opportunity to provide a sort of “enhanced” Steam version. Users who purchase BioShock 2 will instantly gain access to all the DLC for the game (except Minerva’s Den), controller support, added multiplayer tweaks, and support for Steam’s Big Picture Mode. The Steam version also sees the Games For Windows Live functionality completely stripped out and users who purchased the game via disk or on Games for Windows Live can receive a Steam version of the game by following these instructions. The excellent campaign driven DLC, Minerva’s Den is also available on Steam for 5 bucks.