^ Title
Meaning what exactly?
Food requirements, rare loot, more damage, head shot kills, smarter enemies etc?
It's a spoiler (the thread has no spoiler tag) so I won't get in any details. But there are threads on this forum which talk about it with spoiler tag.
Would suggest at least browsing the first page of the forums before posting a question...
http://www.gamesas.com/topic/1542108-no-hardcoe-mode-confirmed/