I'm not sure what could be happening if you haven't downloaded it before.
If you want, add me on Discord and we can take a closer look. My discord username is "rayukiwolf".
:< I'm sorry, I really don't know why this could be happening.
Like I mentioned before, a fresh download and uncompressing the contents into an empty folder works as it should, and no one else has reported a problem so far.
I wish I could help, but I truly have no idea.
I know this isn't ideal, but if you have an Android phone, I'm working on a build for that, so you may be able to play it on your phone.
I'm sorry.