The second official Binding of Isaac expansion, Afterbirth+, will be with us in less than two weeks however the ambitious and impressive user-made Antibirth mod is out now.
Billed as an "unofficial but full fledged expansion" for The Binding of Isaac: Rebirth, Antibirth is two years in the making and features an "improved" local two-player mode—whereby players can control two players simultaneously—a new soundtrack and "heaps of new secrets to be discovered".
Some of that includes over 90 new items and 80 new enemies, 18 trinkets, two new characters "with unique playstyles", a new so-called secret chapter "for those seeking a challenge", 16 new bosses and over 40 new achievements.
I'm yet to give it a whirl myself, but from the little I've seen so far Antibirth looks pretty great. Don't take my word for it, though, have a gander at its launch trailer:
"The Binding of Isaac has had one of the most involved and robust communities of fans around since its initial release and has inspired countless players and developers with its peculiar sensibilities and creative blend of roguelike flavor," reads a message on the Antibirth official site. "As its zealous modding community has proved, it’s only natural that many among us would feel the urge to try to help carry the torch and make it partly our own, but Antibirth was the first and is presently the only Isaac mod to reach deep into the core of Rebirth to enable the depth and scope of a full expansion, aspiring even to the size of the official DLC, Afterbirth.
"If you’ve become as enraptured with Isaac as the rest of us and you still want more, we’re here to provide our absolute best—and more of it than you’ve ever dreamed of—all for free."
More information can be found via the mod's site, including installation instructions.