Hi friend! Yes, nina's art is super nice, and thank you for your lovely words!
We wanted to explain a bit more about how the Sanity mechanic worked, but in the end we didn't manage to add some helper text :( one for a future build for sure!
The way it works is Sanity drops constantly when you switch to the "cursed" dimension (the green one), so that was intended behaviour! It also drops when you get too close to the monstrosities around the labyrinth lol
Glad you enjoyed the bits that you played though! Will check out your game when I can!