OpenRA

Does it start and then crash, or not run at all?
If it crashes it will display a dialog saying "the game has crashed".

Could you paste the contents of ~/Library/Application Support/OpenRA/Logs/exception.log?

Run the Console app (Applications/Utilities/Console.app), and click "Show Log List" if the sidebar is hidden. Select "All Messages" and then type OpenRA into the search field on the top-right.

Copy any messages that it says here.

For anyone else with this issue, we have found the cause of this bug and it will be fixed in the next packaged release.