You can save your game progress in iCloud. For this to work, you need to set up iCloud for your Apple ID. For detailed instructions, please see the iCloud setup instructions: https://www.apple.com/icloud/setup/
When you have set up and logged in to iCloud on your iOS device, you can enable iCloud sync in Zombie Catchers by doing the following:
In the Main Menu of the game, tap the Settings button and select iCloud settings. Select the iCloud Enabled -check box.