When it comes to gosu Diablo people, hardcore mode has always been the mode to be. No other mode, no matter how tough it is, will offer the same thrill and challenge as Hardcore mode.
Diablo 3 Hardcore has permanent death! That's right, your characters are mortal and once they die you loose them forever.
This game mode requires the player to finish softcore on any difficulty to unlock, as announced by Blizzard:
Yes, you will have to play through to a certain point to unlock hardcore mode, I think it’s through normal difficulty after you kill the end boss. I’m like 90% sure, so we could change our minds.
Some things to note about Diablo 3 Hardcore mode:
-Separate Auction House for softcore and hardcore characters
-Only gold Auction House is usable
-Characters can still trade items with each other like in Diablo 2
On death, your items don't drop on the ground so you can stop thinking about having a friend follow you and pick them up and return them later. Items in your shares stash are not lost however.
On player death, an entry is added to the Halls of the Dead in your game account.
Player vs Player in Diablo 3 Hardcore mode has been debated for over 2 years as to whether players should permanently die in the arena or not. The main argument is that if players perma-die in the arena, it will loose it's scope as the pvp arena is meant for fast action and many of deaths. Also many players would just skip pvp. The other side of the coin is that having perma-death in the arena makes for more excting pvp.
In the end, Blizzard announced that there will be no permanent death in the pvp arena, as stated in this quote:
Wyatt Cheng: Our current position is that you don’t die in Diablo PvP in Diablo Hardcore mode. So what happened in Diablo II is that anyone who wanted to do Hardcore PvP would basically level a character to level 10, and then they’d find another level 10 character, and they’d fight and one would die. That’s just not really that interesting. So we’re just going to let players engage in PvP.
It is yet to be seen if there will be an optional perma-death arena, but the default/only option will be no perma-death.
You can find the original article over at Diablo 3 Hardcore