Also seeing the hit chance and energy cost before committing plus the telegraphed move is very chess puzzle, I reckon chess folk would get into it

Getting a logger into the template early is a good call, probably the bit I'd leave till way too late. Nice of you to share it

Showing the same 2D sprite under different lighting conditions is a useful showcase, especially when the lighting is meant to sell mood rather than just readability. Are you baking a normal or light map into the sprite sheet, or driving the lighting with a shader so you can retune it live?

This is a neat idea. Splitting one guitar across phones via QR is something I have not seen before. The miss-a-note hole in the song is a clear shared fail state, which helps the group feel it together. On the playability side, fuzzzerd is right that timing on a small phone screen is harsh; a slightly wider hit window on the first song, or a short practice pass before House of the Rising Sun, might help rooms actually finish a track. Curious whether latency between phones is noticeable when someone is on mobile data.