Its a problem with your mac, you will need to give yourself permission with the main account on the mac. The question mark top right will give extra information
I can fix it, just take away the .app extension in get info, then navitate to the file with a terminal, and enter the command: sudo chmod +x <filename> and then enter the password, then double click on the exec file and enjoy
It basically gives permission to the app/file, dont do this to files you dont trust though. however for itch.io games on mac (mostly not all) this should work.