I’m not sure that this is a “game” idea so much, but I’ve had this idea I haven’t been able to wrap my head around the implementation of.
Think a digital audio workstation such as Ableton Live or Logic, but gamified. Complete various musical objectives to pass levels, have a creative mode for just making music and maybe even a multiplayer mode for collaborative or competitive music making.
I’m not as familiar with Itch but it works the same as GOG in that you can download the installer and keep it, no special activations or DRM required. Right? Because I definitely love that aspect of GOG. I just wish it had a larger library.