To restore non-consumable in-app purchases (character unlocks, Red Gem unlock) please use the Restore Purchases button in the Options menu. This requires that you are using the same iTunes/Android account that you originally used for purchase. You will need to enter your account password.
Ouya players can restore their previously unlocked game by going through the purchase process again. The store will recognize that you have previously purchased this game and not charge your account again.
For lost consumable purchases (Gem Packs, Token Packs) please Contact Us for further assistance.