To turn off notifications:
  • Navigate to device 'Settings'.

  • Choose 'Notifications' .
  • Find the game from the list and tap it.
  • Turn off notification settings according on how you want to, or simply flip 'Allow Notifications' to OFF to turn off all notifications for the game.

  • Completely close and reopen the game for changes to apply. If it still doesn't work the way you wanted you may also need to restart your device.