Creative Mode is a game mode added during the 1.4 update that allows you to have unlimited resources and you decide to have enemies or not during gameplay. Originally, the gamemode was called "Infinite Resource mode", until changed in later updates. Mostly, it behaves like Survival and Free Build put together. In the Xbox version of the game, Creative mode was only unlocked after redeeming a code obtained from the original Castleminer Game. However, in the Steam version of the game, creative mode was unlocked from the start.
The player has to obtain a block first, before "duplicating", or infinitely placing it. When crafting an item, you can produce an infinite amount of the item, until your inventory is full. Bullets in this gamemode are not affected either, so you also have unlimited ammunition.
Note: "Promo codes vary between consoles. Each console includes a promo code from CastleMiner that only works on the same console when entered in CastleMinerZ."