That part when you have to switch between light and dark while jumping between two walls got me stucked xD its kind of difficult to coordinate my fingers, but it's totally the type of game you can get better and better by playing it more, its a skill game.
If you want to continue working in this game I suggest introducing each dimension little by little, at the beginning its very hard to get it :)
There is a little bug, I guess you already know it, that you can get stucked inside a collider, maybe you could add a script that disables the collider if the player is inside so that he can fall an die. But it's not that bad because you can always go void and kill yourself to respawn.