There have been a bit more info about the upcomming DLC for the game
Short list of what's to come:
100+ new items
A new game mode that will "totally change how you play".
10 new challenges
New playable character
New alternate final chapter
New alternate floors
New endings
New final bosses
Tons of new bosses and enemies
New items, cards, pills, etc.
New achievements and rewards for beating the game on hard
New co-op babies
New transformations
More...
http://www.pcgamer.com/the-binding-o...-dlc-detailed/
He hopes to have the dlc ready and released by the middle of the year