Your idea is great for sure. Very original and the presentation is nice. It really shows you did the art and audio yourself, it fits like a glove to your theme and looks cute (especially when angry).
My criticism is the controls. I like the mechanics, but I had such trouble managing the controls! six notes makes sense, but I certainly could barely get shots off in the heat off battle, and the movement not being relative to the camera confused me a lot (though it IS the norm for iso games, so I get your choice :) ). It fit the theme, but was sooo hard to figure out.
I think cutting the notes some could have helped - as could not starting pretty essential spells (like healing) with five notes. Mind you, I'm not that good with games, so it might just be me being very bad at input combinations D: