Ultra Hard is one of the challenges added in the Afterbirth Plus DLC. It's freakin' brutal.

Added annotations to give some insight, I tried some live commentary but found it much harder to play well..
Also people seem to like the no commentary vids more.

In this challenge:
- No heart pickups drop. so items are the only way to get health back.
- All enemies spawn as champions if possible.
- Boss fights will be double trouble if possible.
-These Curses are always active:
Labyrinth - Always XL floors
Blind - Mystery items
Lost - No map
Maze - Sometimes warp to random rooms when going through a door