Hardcore

Hardcore mode is a new game/difficulty mode that is set to be released in a future update. The mode will probably set from the world generation page, and be possible to toggle on or off. Hardcore mode has not been implemented as of the 1.9 pre-release.

Hardcore mode deletes the world when the player dies, and locks the game to hard difficulty.

The idea came to Notch from a Minecraft gameplay blog on the PCGamer site.