I'm experiencing the same issue on the itch Windows app. This error occurs after moving to the right on the first screen of the game. Really interested in what you're going for here, looking forward to being able to play it!
Thanks for adding this! It appears there are issues with playing it with the Itch app, but I have no idea why...I tried to read Itch's "Integration guide" for the app, but it wasn't very helpful in figuring out the issue. I couldn't find anything that would point me in the direction of figuring out why it can be played fine on the site but gives errors in the app...
I think the issue might be that the filepath has an escape character in it (the dollar sign, %24), and while that will work in the browser (the browser needs to escape it, in fact), it may not work with the desktop file manager. This is why I think it works fine in the web version but not in the desktop app.