The Binding of Isaac: Afterbirth

DLC features:

Greed Mode: A whole new game mode with a heavy focus on risk/reward that is a completely new way to play featuring new endings and a final boss
Expanded main game: A new final area has been added to the main game along with another new final boss and ending.
Daily Runs: Compete for highscores / best times on the leaderboards in these daily seeded runs.
10 new challenges
1000+ new rooms, as well as new tiny rooms, closets and giant arching hallways.
A new playable character, Lilith, mother of demons
120 new items along with new pickups, chests, pills, bombs, cards etc.
4 new alternate chapters with new chapter specific enemy types, visual themes, and surprises.
A new seed code combo page, as well new seed codes that mod the game.
A greatly expanded soundtrack.
New room types like trap rooms, double treasure rooms, and ultra rare closets.
A greatly expanded and updated HUD system
New secret transformations
8 new bosses, new variations of bosses introduced in Rebirth. In addition, a few older bosses have new attacks.
25+ new enemies
Updated item combo system
New achievements
New co-op babies