Try this:
1. Go to System Preferences > Security & Privacy > General (tab on the top) and make sure that you have checked "App Store and identified developers"
2. Delete the old installation
3. Download the latest file
4. Run the game (you'll still likely get an error)
4. Go back to the same page in System Preferences and you should see a new pop-up with the name of the game
5. Click "Open anyway"
Hope this helps!