Hardcore

Hardcore mode is a game mode that is a variant of Survival, differing primarily by the lack of the abilities to respawn (instead, the world is deleted) and change difficulty.

Features
While playing hardcore mode, the game is set to “hardcore” difficulty, which only differs from “hard” difficulty in the fact that it cannot be changed to another difficulty while playing the world

When the player dies, the game over screen only offers a button to delete the world save instead of survival mode’s or  buttons. The world save still exists until the button is pressed, leaving the opportunity for one to keep the world by using 3rd party tools. Exiting the client and loading the world again only reloads the game at the game over screen.

History
Hardcore mode was first available to the players in the 1.9 pre-release 2, and is now officially implemented in Minecraft 1.0.

The idea came to Notch from a Minecraft gameplay blog on the PCGamer site, almost a year prior.

Trivia

 * While playing hardcore mode, the heart icons of the life gauge are different.
 * In the world selection screen, Hardcore mode is written in red.
 * When a world in hardcore mode is created with the Beta 1.9 pre-release, then played with the Beta 1.8 version, the world is permanently converted into a standard survival world.
 * In hardcore mode, you actually get a score once you die, as shown in the first gallery picture.
 * When Notch announced Hardcore mode in Twitter, he also posted an image of an "Ultra Hardcore" mode where the premium status of the player's user account is revoked on death. Obviously, this turned out to be a joke.
 * In Hardcore mode, death due to starvation is possible.

Bugs

 * In 1.9 prerelease 2, the "World Is Deleted Upon Death" is present regardless of whether the game is on hardcore or not. This was fixed in 1.9 prerelease 4.