Usually when I see HTML5 games like this, I can "install" them via the itch app to run in a little standalone browser thing, but it doesn't give me that option from the Itch app. I can only see the option to launch this game when I load this game's page in a web browser.
Seems to work for me on Windows 10 with (plain) Firefox and Brave (so, should work with most chromium-based browsers too).
It didn't work for me in Librewolf, even after enabling and forcing-enabled WebGL. There's probably some other setting(s) blocking it in LibreWolf. When WebGL is blocked, it will look like this:
After enabling WebGL in Librewolf, it would show the Godot engine loading. Once it finished, though, it then presented a black screen that you can't interact with. Maybe there's a way to get it working; but, at that point, one should just use a different browser for this kind of thing (instead of lowering the security of librewolf). :p