Today's announcement that The Binding of Isaac: Afterbirth+ is live on Steam was a bit premature, because at this particular moment it is actually not live at all. But it's coming, any minute now, possibly by the time you read this, and creator Edmund McMillen said in a message that while the Afterbirth expansion will "close the book on a five-year journey" that began as just a fun Flash project with a friend, it also marks a new beginning for the game.
"I never had any idea Isaac would become what it has, this little monster has consumed my brain for what feels like a lifetime and I'm at a point now where I can be happy with officially finishing the story and calling the Isaac project done," he wrote. "But as sad as that may sound to some, this is really just the start of things to come. AB+ started as just a mini DLC of mod tools, but slowly ballooned into another game expansion with a bunch more added content… But still at its core the whole point of AB+ was to hand the game off to the community, who at this point knows the game better than i do."
McMillen said that going forward, the game will get monthly "booster pack" updates that will incorporate the best user-made content into the official game, a plan he unveiled back in November. Mod makers don't have to submit their work for consideration—"You can honestly do whatever the hell you wanna do," McMillen wrote—but for the benefit of those who do, he also provided a list of basic guidelines for the content he's looking for, including theme and design tips, ideas about enemies, bosses, and challenges.
Getting your work to him will be a bit of a crapshoot at first: He suggested tweeting a gif or video of your mod in action (but don't overdo it), or maybe posting something on Reddit. "It's a bit hamfisted," he admitted, "but as the months roll by I'm sure we will find a smooth way to exchange ideas and I'll keep updating the blog with new info as the year unfolds."
The Afterbirth+ announcement post also warned that "like any launch there is a good chance that we missed some bugs and players may experience some issues that our testers might have missed." The developers will continue to work on over the launch week, and there may be some nerfing too, if it proves necessary.