Thank you so much, what an amazing and detailed feedback :)
I also thought about switching the controls to always be on the "right" side, but it would probably be very confusing, especially if players are really close to each other ... The controls would swap continuously as players switch sides! Can still give it a try, though.
Yes! Not being able to see when something is in front of something is also my major issue. Your idea about painting blocks depending on the layer also crossed my mind: I think it's possible to make that look good with some shader magic, so I will try that once the game jam is over. Moving the camera isn't possible unfortunately, because the game is completely 2D and there is no camera :p
Haha I do agree the connection to the theme is a loose one. Leaps and bounds => players must take a LEAP of faith, and they are BOUNDED by what the other player can see.
Again, thanks a lot for this response, seriously made my day.