Recognize the entrance
What the doorway looks like
The timed entrance is a broken opening rather than an ordinary hinged door.
Timed opening after Mom
Original game-art examples, shown facing upward where relevant. Door textures and appearance can vary with the floor or item effects.
Find the entrance
How to enter Boss Rush
Beat Mom before 20 minutes, or before 25 minutes on the Mausoleum/Gehenna II route, then enter the opening.
What you can find
Rewards and opportunities
Choose a starting item, defeat 15 waves of two bosses, and collect another item plus the Boss Rush mark.
Understand completion marksBefore you commit
The risk to plan around
Taking the starting choice begins a long fight. Reaching the door in time does not mean your build is ready.
- The entrance becomes available after the initial Mom progression gate.
- Certain item effects, including Mama Mega!, can bypass the ordinary timing requirement.
Useful connections
Items that affect this room
Reference
Repentance rules and room variants
This guide describes the room type. Exact layouts and contents can vary. The rules use Repentance references; Repentance+ can change them.