If you've managed to beat every single challenge The Binding of Isaac has to offer, you'll be glad to hear that The Binding of Isaac: Antibirth, a massive community expansion, has now been released! It brings with it tons of new bosses, balance changes, items, characters, room layouts, and enough new content to keep you occupied for weeks.
And to further cement its place as a 'proper' The Binding of Isaac expansion, Antibirth also comes with a fucked up animated trailer. So if you're up for bizarre imagery, as well as brief flashes of gameplay, you'll find the video right below. Have a look:
As for all of the features coming in with Antibirth, here's the full list of stuff that's probably going to kill you:
• new characters with unique playstyles
• 90+ new collectible items to help Isaac fight
• 18+ new trinkets to swap and strategize with
• 80+ new enemies to face one after another
• 16+ new bosses to kill or be killed by
• 4000+ new rooms to explore and survive
• A new secret final chapter for Isaac to endure
• Bigger and greater secrets than ever before
• Several new or enhanced features for local cooperative play
• A nearly full and original new soundtrack, evocative of classic Isaac
If this sounds like something you might enjoy, you can find the free download and installation instructions by heading over to the official website.
Just keep in mind that Antibirth is a mod for Rebirth, and as such has absolutely no relation to your Afterbirth save file. The developers are working on adding support for all of the Isaac DLCs (including the upcoming Afterbirth+), but that's probably going to take a couple of months. Until then you'll just have to deal with the Rebirth + Antibirth pool of items and enemies, which is already quite significant, so that shouldn't be too much of a problem. Have fun!