Very very cool game idea, and nice use of he theme too!
Obviously, it needs more levels, but as a prototype to test the concept I an say that the game is looking pretty solid! Adding better graphics, even simple ones but with a bit more style to them (for example simple monochrome blocks with just a little bit of bloom and vignette effect) could already make the game pop in my opinion, then obviously sounds and better in-game menus would be the cherry on top.
Looking forward to see more levels of this, as in its simplicity, the concept is pretty neat and clever :)