- By “difficulty,” I meant that you can set a skill level that's a bit more forgiving if you miss the mark, as opposed to a “pro” level, which may be stricter. I’m thinking especially of kids, who might have more fun with it that way. It would also be nice to have a personal profile to choose from, with your own library (?) or at least your own presets (difficulty, progress, etc.).

- It took me a little while to figure out how the app works. You start a song in Apple Music, and the app records it. I had somehow expected a large search bar in the app that I could use aside from the music suggestions to get started.

- Even though I hadn’t set up Spotify (it wasn’t even displayed), it was still enabled in the settings.

- This is probably a bit outside your scope, but in the german song “An Tagen wie diesen, Die Toten Hosen” some (final) syllables get cut off, and sometimes the bars go down even though the melody goes up (or are the notes transposed an octave when they no longer fit within the scale?).

That's for now, I’ll keep an eye on the project and create issues if my observations become more consistent. Thanks for the project!