Very good execution on the idea, SO many levels wow. I'm still playing, at 21 now. Level 16 gave me a lot of trouble for some reason :D I'm really impressed with the design, so simple but so clever and clean. Excellent job!
Btw, we saw this game quite soon after the jam finished and thought "damn someone had the same idea as us". I think it's similar in spirit at least - perhaps you could play ours too? :D