It was fun, original and had a perfect difficulty curve. Although, I experienced some problems playing with TYU-GHJ-BNM mode.
It seemed to work perfectly at first, but when the monsters where you have to press their number (not the position) appeared, some worked, and some others didn't. It detected as if I was pressing the position (which was empty and resulted in penalization) instead of that number. I think this happened specially with nums 3, 5 and 9. I don't know if this happens only without a numpad, or if it's a bug happening only on this pc. Anyhow, it's best if you take a look at it after the jam, so other players don't experience the same issue.
Personally, I felt a bit confused with the explanations at the start of the levels. No big deal, as I managed to learn the system while playing, but maybe you could explore more ways to explain these things. I understand the small resolution is limiting, though.
Oh, I almost forgot: I love the transitions between scenes, and the art in general!
Good job!