It's a cute little game. Good base for a nice puzzle game, but a little on the short side (even if it's a jam game).
Background music - as pointed out - would've been nice, but I didn't really mind the absence of it here.
I also tried my hardest to see if I could abuse the cube-rotation, and I can proudly say it's possible to get one of them into a wall in level 5 (though the level isn't complete-able like that.
Regardless, good game!