I wouldn't think about making a stepmania-like game myself in a jam, so I think it's quite origina. Everything seems well executed, the experience is smooth, although as I'm not that much into rythm games the difficulty was going up quite fast, but it was still manageable so I have no issue with that, just a note to take. The game seems polished and finished (in terms of a jam game ofc), nice smooth menu, cool game over screen, feedback animations from the devil, so that's very very nice, a thing that I always struggle with, so just have to appriciate it even more.
To me in a rythm game the music should carry the game forward, before anything else, and I'm sorry, but to me the music, while the tracks were nice and different from each other, was quite off in terms of hitting the "notes". Maybe it's just me, but I also saw other comments about it feeling a little off. Also as I said, the music should be a stand-out feautre, and here I would say it's just as good as the whole package (which is still very polished and nice, don't get me wrong) but I would say if it's a rythm game I would rather have a grades like that: Music A+, everything else: B, here I would say it's more on a pattern of Music: A, everything else: A (also), but I guess that's just nitpicking.
I have to say I'm impressed by your work in terms of executing the idea all by yourself. Keep it up!