POOR collision detection
This looks like it has the makings of a great game, but the radius of 'invisible ceiling' makes the jump on level 20 almost effectively impossible. All the other jumps to that point are hard but doable, but you spaced the two blocks WAY too close together for the keyboard controls to be able to make the jump. I love the game idea, but seriously fix the invisible hitbox radius that each block protrudes. I've had jumps denied when I didn't even TOUCH the underside, or sides, of another block. 7/10, 3/5