Huh, that's new. Are you trying to download it through the Itch app? I haven't seen anyone have issues downloading it through a browser. I'll try to done some tinkering to see if I can fix that!
So, unfortunately, I cannot send a private message on itch, so I can't send you the download code without needing an email or perhaps a twitter account to DM you. If you download the game on a browser, you should get a zip folder. Then, you right click the folder and hit "extract all," then you'll have access to the game. You should see "Murder at the Cat Show.exe". Click that, and the game should run.