In a new post on the Binding of Isaac tumblr, Edmund McMillen revealed the official name for his next game project after The Legend of Bum-Bo. The next game will be called Øuroboros, and will feature Steven as its protagonist, whom you may remember from one of McMillen’s flash games, Time Fcuk, as well as as a secret boss in The Binding of Isaac. McMillen claims that Øuroboros is not a sequel to Time Fcuk, and is “not remotely a puzzle game at all.”
Øuroboros is an action based platformer/shooter with random level generation and the like, ala Binding of Isaac or Spelunky, but… off.
The post also included a brief trailer for Øuroboros, shown below. McMillen says he has no idea when the game will be done, but is happy to finally give it a name.