Since I've had reports of difficulty opening the Mac version of the previous jam game I made, I figured I might as well copy the potential fixes post from there in case anyone still has problems this time around too :3 Unfortunately, I do not own a Mac myself, so I have no way of testing the Mac versions I export. 

It seems as though depending on the version you're running, opening the game could prove difficult, though should be doable :3 This is the information I've found out so far. I hope it helps!

• This snippet is from user: TofufuL (Thank you :3)
  "If I remember correctly, I tried to see if I could change my settings but that didn’t work out for me (I probably did it incorrectly, I’m not sure, plus it’s risky so I wouldn’t recommend). Then I decided to download Unarchiver and extract the files. If you check the package contents, you should see Unix executable file in the MacOS file, and you can click on that and a prompt will come up saying “can’t open because developer can’t be verified.” Then you can just go to your security and privacy settings and “open anyway,” and it should be working after."

• And this snippet is from user: Zukini (Thank you also :3)
  "I found that you can also left click on the game, select show package contents, go to contents folder>MacOS and left click open the terminal, hope this also helps."

• Aaaand, here's another! This time from user: Evelyn Lima (Thanks :3)
  "For people getting told it won't work on Mac, here's a possible fix: https://apple.stackexchange.com/questions/408752/the-message-you-do-not-have-per..."

The following I found just doing general support searches regarding opening Unity games on Mac:

• You might need to right-click (or ctrl-click) and then select "Open" to get around Mac security settings. Unless you code sign your application you may need to also disable Gatekeeper by setting System Preferences -> Security & Privacy -> Allow apps downloaded from "Anywhere". I highly recommend turning that back on after you start your application if you do end up needing to allow apps downloaded from "Anywhere"
  
  
• https://www.imore.com/how-open-apps-anywhere-macos-catalina-and-mojave
  
  
• Those who download, do not double click it: right click and extract using a 3rd party extractor like The Unarchiver or Keka
  
  
•  Double click the extracted app, Mac will show a message saying that it is not allowed to run - Go to system security settings, unlock it and click to open it - Now it should work!