All right, I got a chance to try this for real this time.
Admittedly, I'm not into roguelikes, so I'm not the best person to judge. But I can say that the concept is really cool, and I like the whole lore/setting.
It probably takes some practice to get good at it, because there's a bit of a clash between playing safe/conservatively (because permadeath) and playing loose/having fun (because the rhythm game mechanics encourage you to play by feel). I don't think that's a bad thing, though, and furthermore it seems normal for the genre. If I were playing more seriously or for a longer session, I would probably take a step back and play more safe to start with - and then try and match the rhythm later on.
Btw, I wonder if it's worth adding some kind of EQ to boost the volume of the bass and snare. This is one of the few rhythm games where the audio cues seem more useful than the visual cues. That's really cool, and I think it's worth leaning into.