The expansion will sell for $10.99. The Wii U version of Afterbirth will be released "in the coming months," according to Nicalis.
Afterbirth is a major add-on that introduces an additional playable character, Lilith; more than 1,000 new room designs; four alternate chapters; Daily Runs; the new Greed Mode; all kinds of new items; and more. The expansion offers "more than 100 hours of additional gameplay," according to Nicalis.
The Daily Runs mode sounds similar to daily challenges in Spelunky. Every day, Afterbirth generates a new run for players to try out; each run is identical for everybody — including the character they play as — and it's all about competing for leaderboard glory. You don't unlock or earn anything in Daily Runs, or make any progress.
Greed Mode offers a wave-based challenge in which you have to defeat groups of randomly chosen enemies that spawn around the room. The waves get tougher as you go on, but if you can make it through eight of them, you'll be able to cash in your winnings. It doesn't end there, though; at that point, you can try your hand at "boss waves" and more challenges.
Afterbirth debuted on Linux, Mac and Windows last October. Developer Edmund McMillen is now working on a second expansion for Rebirth called Afterbirth+; that add-on will also come to consoles, but only PS4 and Xbox One, and not at the same time as PC. Afterbirth+ will introduce developer tools that will enable support for mods, although McMillen said last month that mod support will be unavailable on consoles. As for an iOS version of Rebirth, McMillen said, "We haven't given up," even though Apple rejected the game earlier this year.