These are things that you need to improve and that are a problem for all the beginners (Im in that group too) and can only be improved with practice.
- Collision box: the collision box wasnt right, and I got hanging by the side of the character and I could jump in places i didnt suppose to (it seems that you used the sprite as a collision). How would I fix it: I would make an invisible box arround the character and I would test the collision with it.
-Music: It was unique, but the melodic line was a strange choise and it felt out of context with the harmonic line, It was distracting but that just me.
The art work was well made and I think your game has potential, thanks for making it!