hey it's very relaxing, thank you !
i find a great potential with this concept, and while playing with it i had some ideas i want to share with you :
make it more interactive by adding challenges : Bonuses when we do a beautifull chord (so we have to remember wich color is wich note), and when we do combos of notes, scales...
The random apparition of Bubbles is good, cause we have to stay alert to find the right note to make a melody, and the left right jiggle also because we can wait that two notes come close to each other to do a chord.
it's like a new intrument when we try to do melody with it hah
it has a Bullet Hell vibe also