
So many items, rooms, enemies, and systems have been tweaked, rebalanced, and reworked. The update notes showing changes between Afterbirth+ and Repentance are huge. Cooperative multiplayer is still officially local-only but it does support Steam Remote Play for online.

It also adds proper co-op, with selectable characters instead of those lousy babies. It's made with some of the folks behind the huge mod Antibirth, and many of its additions are based on that, though loads is new too. Repentance expands Isaac again with new items, playable characters (including one that's actually two character), floors, enemies, bosses, room layouts, achievements, and challenges, an art style tweaked to be a bit closer to Flash Isaac, and a new final boss with a new ending. I cannot tell you how much it is killing me to have to 'work' and write this post rather than sack it off and go play right now. Repentance is a huge send-off, adding loads of newness while improving the old too. After six years, The Binding Of Isaac: Rebirth has finally launched its final expansion (though the previous one was supposed to be its last).
