First of all, let me tell you that's it a pretty innovative thing to create a music-based puzzle game - so you've faced a real design challenge, and I give you many props for that! :) It was a formidable task you let the player face, because it really got harder and harder over the time to figure out which instruments belong to the songs (especially for non-musical people like myself). But I loved each second of it. <3 Thanks for your game, I wrote a little article about it as well as made a gameplay video of it, hoping that more people might try it out. :)
Best wishes,
Sebastian