Now that's a neat interpretation of the theme! I like the idea of having to find notes that sounds like they fit in the current music. I wished the game allowed me to hear the entire scale, during the level to better hear if a note is part of it or not, and at the end as a reward. I could still rely on the visual notes writing, but I find it less fun. :P
Also I'm missing a C in the Level 3, I went back and forth but couldn't find one.^^' But beside that, it was pleasant to complete. Kudos for this clever use of music and sound!