Ah, I got that error too ! Apparently it's because of mac's very stringent security. To get it working you'll need to pop into the terminal and disable the gatekeeper from there (but turn it back on after you're done). This will allow apps from 'anywhere' other than the app store and identified developers. After that you might also get an 'unable to find game' error to which just move the iron ferret app to any other different folder and run it. It should be fine after that and you can move it back to the original folder. Thanks for checking it out too <3