"The rest aren't out of the question. We would love to release on all systems; the ball is in their courts though. We miiiiight also test the game out on iPad and see how it works – if it works ok then we will also release there." McMillen would love to see Rebith on Nintendo 3DS, but that's not possible right now, he says.
"We want to release on 3DS, and will if given the option," McMillen writes. "Isaac currently goes against Nintendo's publishing rules due to its religious aspects. But stuff might change, you never know." He mentioned the religion issue regarding Nintendo in February 2012, but still called out 3DS and Wii U in November 2012 as platform goals.
Rebirth features local co-op and the ability for players to stream runs against other people online, plus the option to share your final, end-game Isaac avatar online. It also supports controllers and will have at least three new playable characters, new endings and chapters, and more than 150 new items, pushing the total item count past 300.
For clarity's sake, the header image is not an in-game screen of Rebirth's new art of anything. It's a Monstro figurine from The Binding of Isaac, hand-made by McMillen's mother-in-law and eventually available to purchase here.