Nice job - reminds me of the old game Synthesia which uses a similar falling note approach to teach piano. One nice thing about it is that it lets you switch between the following notes and actual grand staff sheet music.

https://synthesiagame.com

If she’s interested in learning to play by ear, I created an educational game called Lend Me Your Ears in the style of the old “Simon” toy. It presents players with a sequence of musical notes that increases over time and challenges them to reproduce it by ear using either an on-screen piano, a connected MIDI keyboard, or an acoustic instrument.

https://lend-me-your-ears.specr.net