I was able to run the game on my Mac with this trick given by the OSX user guide (which also means you trust Andriy 100% not running any malicious software with the game):
Open an app by overriding security settings
You can open an app that isn’t allowed to open by manually overriding the settings in Security & Privacy preferences.
- In the Finder
on your Mac, locate the app you want to open. Most apps can be found in the Applications folder.
- Control-click the app icon, then choose Open from the shortcut menu.
- Click Open.
The app is saved as an exception to your security settings, and you can open it in the future by double-clicking it, just as you can any authorised app.