tried downloading the Mac version and it wouldn't let me open it cause it couldn't verify there was no malware :(
Pull up that little pop up again, and press the little question mark in the middle. it'll show you a page that says something along the lines of settings, press that- itll take you to settings, scroll and find a tab that says the name of the game, and allow it to run. When you do that itll ask if you want to run it anyway, put your password in and itll play. Hope this help, look up a youtube video if you need to.