From the start platform, a staircase goes a floor down. Turn left, another goes a floor up. At the top, to the left, a misaligned texture: secret door. And small, nasty people everywhere.

This is daft. After getting to the red key, you get to this room. There are two concealed doors - one across from the entry, the other across from the skull switch. This door leads to no less than 19 secrets; every bit of floor and every stair step is a secret.

There must have been alcohol involved.

Exiting from #2, turn left. There are a red torch on each side of the wall opening. The torches each stand in a secret sector. And you can not get to them.

I can't see any point with this; i still believe alcohol was involved. If anybody can find a way to trigger these secrets without the 'noclip' cheat, pray tell.