There are hidden chests in some of the normal rooms. A simple graphical guide to the ones I’ve found so far.
Hidden Chests
Random Room 1
Random Room 2
Random Room 3
Random Room 4
Random Room 5
Random Room 6
Random Room 7
Random Room 8
Random Room 9
Random Room 10
Random Room 11
Random Room 12
Random Room 13
The chest is hidden in an alcove in the lift shaft.
Random Room 14
Chest is at the top of the room, can’t miss it.
Random Room 15
On the bottom floor there are platforms on one of the sides. Going through the small platforming you can get to the entrance to the place of the picture.
Random Room 16
Room 15: On the bottom floor there are platforms on one of the sides. going through he small platforming you can get to the entrance to the place of the picture
Thanks mate!