Diablo III is the third installment in Blizzard's franchise. The game, like its predecessors, is a dungeon crawler in which the player fights against hordes of enemies ranging from beasts and undead to actual demons. The game has four acts, two game modes (normal and hardcore) as well as four difficulty levels: Normal, Nightmare, Hell and Inferno. A new addition to Diablo III is the auction house, where items are exchanged for in-game gold or real money, also usable to purchase Blizzard merchandise. The game features a wide array of achievements earned upon meeting certain requirements.