As part of a Diablo III panel held at last weekend's BlizzCon, Blizzard revealed new details on the game's four difficulty levels, including the brand new, extra-punishing Inferno mode.

Anyone who's played through Diablo II on Hell or Nightmare difficulty is well aware that the challenge ramps up significantly between the various levels, but the differences in Diablo III will be even more significant. With a player level cap of 60, enemies on Inferno mode will be able to reach a whopping level 61, and there will be a greatly increased chance that you'll encounter rarer, more powerful variations of monsters and champions. These more lethal foes will sport up to four added special abilities, including a greater emphasis on area of effect, ranged attacks, and area denial, making it a lot harder to utilize the same basic strategies.

Of course, the benefit of the added challenge is the promise of better loot, with top tier gear only available on Hell and Inferno. In fact, 70% of all the items in the game will only appear if you're playing on a difficulty above Normal, both to streamline the experience for new users and to reward those who take on the harder modes.

To make the challenge a bit easier for players who like to go it alone, Blizzard is also promising a greatly improved follower system. In previous games, hiring a companion to follow you into battle on anything above Normal was nothing more than a quick way to lose money and watch some poor mercenary chump die, but improved AI and upscaled characters should help remedy that.

Diablo III, currently a PC exclusive, is slated for release in the first quarter of 2012.