Well, I definitely figured it all out. However, it would have been SUPER duper hard if I didn't have an idea of what to do. I think if you expanded this, it could be a really neat game that teaches music theory. Honestly, it just needs a bit of simplification and tutorialization and you could lead someone from no knowledge to what you did. This is like a middle step game. Following the melody was probably the hardest part due to phrasing and all that but it made sense in the end.
For what you made though, if you have the prerequisite knowledge, it's definitely fine!
Great work!