This is really strange. As far as I can tell, it's nothing on my end. As the OP discussed, you should try opening it on another device and see what happens. Otherwise, you may need to contact itch support. In the meantime, if you are unable to open the file on a different device, I am happy to send you a copy of the PDF and any other materials you are unable to access if you provide a way to contact you. Is it the .zip file that you are unable to open or the PDF?