If you work an a story, that might be interesting.
But I do not understand how you would spend money on your game to improve it. Unless you would need to pay a coder to do it for you. Most people here a developers in the sense that they would code their own game. And that only takes time and not money. It is a hobby for most here.
The prototype is basically not playable on Chrome. After ages it seemed to have loaded and all the assets were black rectangles that sometimes flashed to be a tree or a rock. I could walk around and eat fruits and that was it. There was no story in the game.
You are a musician, so you probably know best how many notes you can copy or have similar to another song and be ok. I do recognise that the mana song is a bit different, but I also recognise that some sequences sound rather the same.