Visually it looks great, it also sounds great. Folding space mechanic fairly straightforward in being able to grasp how it works with some uncertainty as to what ends up folded and what doesn't. Resulting in a lot of trial and error. Puzzles are fine -- I don't like puzzle games so I can't really comment; actually don't like 2D platformers either :p.
I think switching between WASD and SPACE for character movement, and then the mouse in order to fold space is awkward. I have no solution for you, it is what it is -- maybe a button to toggle between character movement with WASD to moving the folding space reticle with WASD. I mention this in that 2D puzzle platformers in order to do well on Steam need to be exceptional in all areas; otherwise they will not sell well. Can't have any sticking points or hope that players will overlook weak areas of your game.
So with the controls being a bit awkward as you have one hand -- my right -- moving from space to the mouse in order to fold space, well that to me is awkward. Also, does this have controller support? Any 2D platformer should have controller support and be completely controllable with a controller. So in my opinion, your folding space mechanic would need to be handled with a controller as well.