Man, this was probably the most unforgiving game I played during the jam, but I kept hammering at those levels because the concept is that good and I just had to see the next level. Great work.
You know the obvious feedback for improvement, (art, more juice, themed levels down the line, slightly easier difficulty curve!), but I also think it might be nice if there was a visual indication of where the overlap between boxes was occurring ... so think of like a Venn diagram where you know what part overlaps. I think this would look pretty awesome, but from a gameplay standpoint it would make some of the more frustrating parts (not difficult jumps, just odd timing because you didn't know where the overlap was) less frustrating.
What an excellent concept and I hope you keep building on this game as I'd love to play it again when you've had more time than 48 hours with it. Great work.