I really wish I could say I enjoyed this – it's a really cute concept that reminds me of Captain Toad, and the puzzles themselves were well-designed and required some thought – but the lack of polish really dragged it down for me.
My biggest problem is how you both insert the music notes and interact with the instruments automatically by just walking into them. I would often insert the note when I just wanted to interact with the instrument, or vice versa, and it eventually got to the point where I was screaming at my monitor because I kept bouncing off a yellow harp when I just wanted to put an orange note into it. I'm not sure what the best solution would be (maybe letting you throw the music note a bit in front of you, or exchange the notes with a button press), but it's something I thought really needed to be addressed.
There were some other physics issues that resulted in things like notes occasionally getting out of range, or puzzles being solved in ways I didn't think were intended; and the UI could use some improvement; but those are relatively minor compared to the aforementioned issue. Again, I wanted to like this a lot, but the problems irritated me more than I expected.
Out of curiosity, is the $1.64 in the top right corner at the end supposed to be some sort of ranking?