I have a thought for a machanic that I might include. The entities that you meet in The Endless Rooms have mostly forgotten who and what they are. I have been thinking that memories could manifest like little flappy moths or butterflies which you must catch and return to their owners.
To that end, I’ve been sketching some ideas.
The plan here is to use mirror symmetry and so I have only drawn one side of each.
A planned machinic is a hidden sanity meter. Sanity is reduced slowly over time but more quickly while in unlit rooms or interacting with the more eldritch elements of the maze. As the meter gets lower, strange things may start happening, other lost souls will be drawn towards you, and some of what you find may or may not be purely in your head. If it hits zero, you will find yourself reset to the starting room. Not everything resets when you are reset.
As your sanity reduces, your vision narrows, meaning that you may miss things on the first pass through a room.
Another effect of rooms in total darkness may be disorientation. This means you might take a side door out rather than the one in front of you.
This is a central part of the gameplay loop. This sanity and reset loop is what you are trying to escape by finding the one door that (for you) leads back to the real world.