The World of ULTRAKILL

Exit the elevator into a white courtyard and enter the marble labyrinth.

In the first room, the left doors close, and the right is locked. Proceed through the center doors into a gallery with Mannequins.

Reach the far door, a red pedestal rises. Return to the first room; the previously locked door is now open.

Navigate a narrow corridor and wall-jump to a higher floor. Enter a room with an Alpha (α) button and a blue pedestal. Pressing the button unlocks a door elsewhere.

Return to the first room; the door that previously closed is now open. Enter the room filled with stationary Mannequins.

Proceed to a kneeling Mannequin behind a gate to obtain the Red Skull Key.

Return to the Mannequin gallery room and use the Red Skull Key on the red pedestal.

Six Mannequins will attack. Defeat them to unlock the path forward.

Descend the split staircase into a room with a walkway. Mannequins will emerge from below.

Continue through the level, encountering various enemies including Strays, Schisms, Soldiers, Drones, Streetcleaners, Mindflayers, Malicious Faces, Cerberi, Mannequins, Virtues, and the Minotaur boss.

The secret encounter involves fighting Big Johninator.