the musical modes idea was really clever. it's also impressive how long this game is (given you made it in a week!)
if i HAD to say something about its flaws i'd probably target the controls- they're a little slippery on the ground and not fast enough in midair; and the jump is a fixed height (you can't fall faster by letting go of the button). and i think you made all the sounds as well?? those are a complete highlight. it feels really impactful to finish a section or jump on a platform (drums? spaceships? idk).