you basicaly just beat normal, then game restarts in nightmare, then beat that to get to hell mode, then finally inferno. gear you had when you win a mode stays with you. in the next mode everything is harder and the gear is better. think of it like WoW dungeons and then WoW heroics. like 10man ICC (normal), 10man ICC heroic (nightmare), then 25man ICC(hell), 25man heroic (inferno). once you get the game let me know. i end work this thursday so i can run you through some parts of the game if you want anytime this week at nights