Thanks for the feedback!
It is indeed a 2D game with simulated 3D physics. I changed the scale of the sprite to show the perspective and I trigger the mask of the platforms on/off if you touch the void to make you fall down. Then I needed to check from which point you dropped, to fall down at the same spot the layer below. It was quite complicated (for no good reasons!!)
In retrospect, I think I should have gone 3D with this one, especially in a 10-day jam. I'm still glad I did it in 2D though, I learned a lot about how 2D physics work.
Thank you for playing, I appreciate