Well from itch.io of course. I downloaded it after I bought it.
Oh, that's good. I've seen people pirate games in the past and then go to the official channels to complain about it not working. Did you use the web browser, or the desktop app.
I haven't seen this problem with this game myself. But my suggestion would be to uninstall and reinstall. If you have played it before, copy your save files to another location before uninstalling