Wow, this certainly looks to be quite the RPG you're making! First impressions are incredibly positive as the visual presentation is very impressive, the world and characters are charming with lots of goofy dialogue, little interactions and lively animations, and the combat being challenging and unique with its music/rhythm-based mechanics. Overall just smacks of extreme potential and I'm looking forward to seeing how this develops!
In order to help that development, here's some feedback:
*Really wish the game had some sort of save system, especially since it's a long experience to play through at the moment in one sitting, but also because it would be more helpful to experiment with the systems and provide more feedback!
*Find it weird that the defense input is colored red when all the other inputs are consistently blue. I guess the intention is that defense is used on red notes? But because the defense note is colored red, it makes me think it's disabled/locked or does something bad or something. Just strange.
*I thought it was a bit too verbose and confusing when explaining the special move mechanic. First, I think you just need to say that if you hit notes correctly, you'll build up your bar and can do a special move when it goes green: don't bother explaining all the numbers and junk, keep it simple! Second, when it said to do the special move on a 'free note', I thought it meant empty space, like a black line: I didn't realize it meant to use it on a normal/attack/white note.
*I don't mind getting lost to a degree, but I found it a bit weird that there is no straightforward dirt path from the house to Joh at the start: makes it really confusing to determine where to go at the beginning and you could get roped into a lot of fights and such that you might've thought were necessary.
*Difficulty is pretty hard starting out for combat, particularly the mushrooms, where it is throwing in some challenging note charts with all sorts of tricky melodic beats. This early on, I think it should stick to something easy like strong beats. I suppose it's nice to get a preview of where the combat will build up to though, but I just think it's too much too soon!
*Defeating enemies results in the game freezing in an unsatisfying manner: I actually thought the game broke when I won my first fight since it was so awkward! We need some more fanfare and a satisfying death animation for the enemy instead!
*Combat is nice, but there's something unsatisfying about it. I'm just not able to feel a satisfying connection between pressing the notes on time and fighting the enemy: I need stronger and more satisfying feedback, particularly sound effects, to let me know I'm making progress in the fight. Another reason for this vague disconnection might be that I can't focus on the combat animations because I'm too busy looking at the notechart: maybe there's a way the UI can be redesigned to keep both visible?
Hopefully this can help!