I visited this page in Firefox and was presented with a message that essentialy said (paraphrasing): "this site best viewed with browser X". Now, I'm not a professional web developer, and maybe there are legitimate reasons why this app is depending on new cutting edge browser features that aren't yet supported by Firefox, but it seems to me that this just shouldn't be a thing anymore.
You can load and get into game with Firefox, you can click the proceed anyway link at the bottom to try it, however performance is worse and some features don't work.
Namely Firefox is missing support for the `FileSystemFileHandle` locking mode which prevents multiple tabs from running (cannot share file handles), and they have a negative standards position on implementing some other parts of the File System Access API like `showDirectoryPicker()`.
