Dragon Endurance is a hidden game mode in CastleMiner Z that can only be unlocked when a player finally kills the Undead Dragon in Endurance Mode only. After you unlock the game mode Dragon Endurance, go back to the main menu and select whether to play it alone or play it online with your friends. With that, it functions like survival, since it lets you choose your map. Remember that in Dragon Endurance there's no common Undead, except for skeletons in caves, and aliens at alien crash sites. The only enemies you'll be fighting on the surface will be dragons. Dragon Endurance is recommended for experienced players only due to the intense dragon combat.