Gems

Gems are the premium currency.

You can get Gems for every 10th floor completed, as daily reward, by watching ads, paying real money, and redeeming Coupons.

Gems are used for buying coins, upgrading Golden Key, buying costumes, buying and upgrading pets, and buying boosts.

Hints

 * Do not spend gems on pets unless you are very impatient, because pets are unlocked after reaching various stages.
 * It may be a good idea to save up some gems to upgrade Golden Key very early in game.