I like the concept, it has a lot of potential! I really like how you have to mess with the different kinds of blocks with their different gravities, and how the gravity is uncontrollable for the player (mostly) but still feels fair because it's at a pretty constant rate.
Got up to the impossible level on one player, got 19 rooms cleared. :) I think it's great you made your own audio for the game as well! I love video game music. Maybe just bring up the music an octave? It's hard to hear when it's so low.
Good work and good luck in the future! And I'd love it if you could rate my game as well :)