Honestly no idea. Here are some suggestions to make it past the loading screen : while it's loading, do not click in the screen nor press any button; deactivate your antivirus (or create an exception for the executable) since some older Unity loaders are misidentified as a threat; make sure no other demanding executable is running at the same time in the background.
If all else fails, you can demand a refund from Itchio and receive our apologies for the trouble.