You can use iCloud to backup the data (savegame, achievements, etc), then you can restore it on another iPad using the reversed way but you will need to activate the game which can be done by contacting the company and provide the UUID and all the registration details. You can find the UUID on the game page on the App Store. Once you submit these details, a new serial number will be issued based on the UUID which you can use to re-register the game.
