Now didn't I just finish the secret level!

This rather intricate purple brick maze is filled up with ghosts and SS.

Look for the four secret areas for powerups, a chaingun is found in the western one, a 1-up in the southern one. But when you thought you had finally rid the maze of every SS, whole bunches of them are infesting it anew.

Follow the crowns to get to the rooms with the Gold Key and the Silver Key. But you may get someone to open the silver key door for you, which is leading to the elevator in the south-western corner of the floor. And here is yet another ghost. The first elevator is a dummy. In the next room you find the real one. With a Fake Hitler.