This is great! Please consider even easier settings for kids. Maybe 2 notes (not 4) as the min starting point and slower ramp up as you succeed.

Also, I think the missed the first note UI could feel a little nicer. Something about the popup/hiding the music takes you out of the flow. Possibly just a subtitle would be enough with an encouraging message. There is a big difference between failing to do the whole pattern and failing the first note so definitely worth refining the feedback here.

This is good feedback - I'll add it in the next version! I actually wrote this for my younger sister but she already has some musical training so it isn't as geared towards beginners.

As a non-musical person, I went looking for how to set it to 1 note!