Fun idea, I wish I got to use more green blocks (though I get how that could have messed up balance issues for your puzzles). With some sound and a few more levels this could be a pretty fun game. Great job!
My original plan was to make a whole bunch more colors and mechanics such as teleporters (which the pink/purple was originally but I couldn't get it to work properly so I changed it), speed boosters, launch pads, a small jetpack like thing to glide and I was going to add enemies which you can only attack when you're red but stuff got in the way sadly.