You can adjust your notification preferences on your device's Settings. Open Settings, then tap on the Notification Center bar and locate the game icon.
If you wish to completely disable all notifications, make sure to set all options to "OFF", otherwise just select from the menus listed the ones you wish to disable/enable.
- Open the Settings menu from your home screen
- Locate and select Apps or Application Manager
- Find the app and uncheck the Show Notifications checkbox