Well, that was nice! Some puzzles felt a bit awkward, but as stated in the description, it's still a work in progress. But I enjoyd exploring the island, and finding all the tapes. The most annoying glitch as of now might be the out of bounds that happens on the wrong end of the Harmony Path. It forced me to exit the game and do all restart from the beginning. But despite that aspect, I think it was the most interesting puzzles. Although for players who are unfamilar with music theory, I think it would be nice if they had a room who would show them what major and minor chords are.
Some little details: the "ending" was a bit tricky to find. Once I got all the tapes, I just wandered on the islands, and sure I remembered that one case that I couldn't enter, but I didn't expect it to actually be where I should have been going! Also, while going out of bound, I'm almost sure I saw a castle in the distance... Was I hallucinating, or is there some other content still unreachable as of now?^^
Anyway, while it sure is a bit clumsy here and there (most puzzles need better feedbacks), it's still quite enjoyable. Good job!