I really like the potential in this game, the aesthetics are really cool, and the main character is really charismatic. That said, the difficulty curve is too steep in my opinion (maybe I am awful). Even though the platforming spaces are fascinating, they become too hard too quickly for me to get used to, and I have to try too many times. In fact, I rage-quitted, I will admit.
The wall jump is hard to get right, and there are not many parts where you can practice it in an easy situation. It feels really strange that moving towards the wall and jumping takes you off the wall. But that you can get used to.
The dash has some weird controls. It is mapped to the mouse, but the mouse position is not what determines the direction. If the mouse is not going to influence the dash, in my opinion it should be mapped to a key, since this way it feels really weird.
For the combat, I love the idea of having to time your attacks with the music, but I really did not get the feeling well, it was a bit clunky, maybe it lacked some feedback? My feeling is that I did not get your idea right, which is a shame, since, as I said, it is a really cool mechanic. In the end, I just hoped for combat to end.
To end with all the things that were done well, apart from the aesthetics already mentioned, the level design is great, I did not feel lost at any point, and it taught me well the mechanics (as I said, I would probably need some easier platforming spaces before the difficult ones). There are many save points, which I feel is a great decision for the style aimed for. And the game is fun, which is the most important part. In fact, all the things I said can be neglected, but fixing them in some way might make the game an awesome experience.
(As a game developer, I know not everything I said can be applied as some things might go against your view, but knowing how I feel can help you get your view more accurately)