Secret Places (5)
The first secret is the hardest to find. Use a jetpack and search the blue building wall outside for the graffiti shown in the image. The window directly above the graffiti is not solid. Fly into the window to find the secret.
This switch is near the car. After hitting it, go to the phones near the entrance. A secret has been opened in their place. (Note: This room has flickering lights. This snapshot was captured in the split second that the room was lit, to increase visibility of the surrounding area.)
Go to the room behind the one-way mirror. Press on the sound equipment to open a secret door on your right.
The bookshelf beside J.McClain's desk can be opened. It leads down to the area visible from the beginning of the level. The actual secret place is by the wooden pole.
The map behind the yellow access card desk can be opened.
Secret Messages
"Open Judge Dredd". Hidden in a dark corner nearby the blue access card (nightvision goggles required). Refers to the location of the secret level nukebutton.
Secret Level
Open the picture behind the judge's desk. This is probably the easiest secret level to find in the entire game. It's even easier to find than the regular ending. The secret nukebutton warps to Area 51.