Ah crap, looks like I built the game using the new unity 6 WebGPU render stack, and it appears that Firefox has not rolled support for this out fully, and so the game appears mostly black.
I know it's a lot to ask, but would you care to try it in Chrome (or other similar WebKit browser)?
Otherwise I've re-built it with the WebGL 2 .0 option instead: https://schme16.itch.io/davos-discount-gallery-firefox
If I could update the game I'd just rebuild it in the standard render stack, but the game is of course locked for judging.