This is a problem that can happen almost randomly to any kind of Mac app. It has something to do with the Mac App Store corrupting a file when it is downloading updates to an app. Here's how you can normally fix this issue:
1.) Log out of the Mac App Store: Open the 'App Store' app and from the App Store's menu bar, choose 'Store > Sign Out'.
2.) Reboot your Mac.
3.) Open the 'App Store' again and log back in to the App Store (Store > Sign In). Now start up the game to see if it works.
If it still doesn't work, try to delete and re-install the game as explained below. Your purchases/progress should not be lost if you delete the app in the way mentioned below:
1.) Within the Launchpad app on your Mac (it looks like a rocket ship), click and hold on the game's app icon until it starts to shake, then click the 'X' icon that appears above it to delete it properly. Do not drag the app to the Trash or delete it by any other methods.
2.) Log out of the Mac App Store: Open the 'App Store' app and from the App Store's menu bar, choose 'Store > Sign Out'.
3.) Reboot your Mac.
4.) Open the 'App Store' again and log back in to the App Store (Store > Sign In), then switch to the 'Purchases' tab and click the 'Install' button next to the game to re-install it.
5.) Now start up the game, restore any purchases from the Options/Upgrade screen, then exit the game, and re-start the game, to see if it works properly now.
If it still doesn't work, please contact us!