I feel completely inept to judge the mechanics, so I'll leave that to someone who actually has rhythm. :D
This is an extremely high-polished game, down to the little details. It's very punishing, but maybe that was the vibe you were going for. For someone who hasn't played Crypt of the Necrodancer or any similar games, it was a bit overwhelming at first. The only thing I could suggest is a more forgiving difficulty curve. You already got the presentation covered. :)