Hi, thanks for letting me know. replying to you just in case you don't see the above reply. two solutions:
- download the game through the itch.io app (itch.io/app)
- open up a terminal window and type xattr -d com.apple.quarantine and then drag the downloaded .app file onto the terminal window so it will add on the full path to the app. make sure there is a space between the .app path and the command. press enter and then try to open the .app file again. (this article goes into a little more depth and has some screen caps to help https://help.yoyogames.com/hc/en-us/articles/216753558)
let me know if you still have trouble