Consider if you can simplify the game so that it's only played on one or two octaves, and the full range is shown at all times. I believe that's the best way forward.

Maybe a simple mode (one octave) and an advanced mode (more octaves..).

Thanks for the nice game! And because there is a keyboard right there to compare with the recording, this is just as much a game of relative pitch as it is perfect pitch. (With that said I don't mind the name, it is a fun one and can be good branding.)