Thanks for the comment.
If you are unable to run the HTML5 build on linux it may be something on your end, or maybe something on itch's end. You said you are trying to running it on the desktop app and it doesn't work?
2 years ago(+1)
The desktop app doesn't launch it right, but I went into the ~/.config/itch/apps/grave and ran it from there, it works in browser. It's something with the desktop app. I'll go to the github page later and see if anyone can figure it out.