There's a reason "Diablo 2" stuck around for as long as it did. The core game might've only taken a dozen hours to complete, but it encouraged constant replays with progressively higher difficulty levels which had better loot drops and offered more of a challenge to skilled players. You started off with Normal, moved on to Nightmare and wrapped things up with Hell. Once you got to the end of Hell, the loot was as good as it could possibly be, so people would constantly run the same quests over and over again to try and score the best gear. These became known as Baal Runs, as they culminated with a battle against the final boss of the "Diablo 2" expansion pack, Baal.

Blizzard doesn't want the same thing to happen with "Diablo 3." Outside of a dedicated group of players, most people find running the same quest dozens of times no fun at all. An an attempt to mix things up, Kotaku is reporting that the developers have introduced Inferno mode, which sits on top of even Hell.

In Inferno mode, every single enemy you face will be at least level 61 or higher. The "Diablo 3" level cap is 60, so you're always going to be fighting enemies that are higher than you. In short, this will make the game very hard.

But you will be handsomely rewarded! The loot in Inferno is the very best the game has to offer, including exclusive weapons, armor and runestones. It also offers more variety, as the highest level enemies won't just be in a single location. Instead they'll be scattered throughout the game, so players will have more options when going on loot runs.

The addition of Inferno mode should ensure a long, healthy lifespan for "Diablo 3." As for when we'll be able to start that lifespan, it's anyone's guess. At present all Blizzard is saying is that the beta should be out by September, which is in keeping with their Q3 promise from a few months back.