It looks like there is an incompatibility between Unity’s WebGL template and the way the itch.io app runs browser builds. I have a few ideas for fixing it, but since the GMTK jam is currently in its voting period, I’m afraid we aren’t allowed to upload updated files.
In the meantime, this issue should not affect the native Windows version or the browser version played directly from the itch.io page. If possible, please try one of those instead.
I’ll investigate the problem further and publish a fix after the voting period ends. Thank you again for reporting it!