Yeah, it seems to be an itch.io problem with access premissions. They have not enabled chromium OS level functionality access such as file browser or clipboard. I attempted to make a save function so users could at least save a text file but that's restricted to the siloed web cache so I can't even allow the user to save to, like, downloads folder or whatnot. Not much I can do about it except put the little warning in the description.
Three workarounds are: download the .exe file and run the game locally, run itch.io in a non-chromium browser like Firefox or play the game from newgrounds since they've set up the chromium premissions. https://www.newgrounds.com/portal/view/981053