Hardcore Mode

Hardcore mode is an achievement/trophy, as well as a gameplay mode in Fallout: New Vegas, that introduces new aspects of survival into the game play.

Achievement
The achievement is awarded for completing the game from start to finish in Hardcore Mode. The mode is initially available just before you leave Doc Mitchell's house for the first time and the player is given the achievement/trophy for keeping hardcore on continuously from this point until completing the main quest line. Switching off Hardcore Mode at any time during the play through will prevent this achievement from being awarded.

Game mode
Hardcore mode can be toggled off at any time through the options menu. Once turned off, it can't be turned back on.

In this mode, stimpaks heal over time, RadAway removes radiation over time, ammunition has weight, and the Courier must stay hydrated, eat periodically, and have a regular sleep cycle. Food only staves off hunger and heals you over time. To restore critically damaged limbs, you must use a doctor's bag, hydra, or visit an actual doctor. Sleeping does not heal health points or crippled limbs, unless it is in an owned bed. In addition, recruited companions can die permanently.

Status Effects

 * Note: The hours are for game time; the seconds for real time.

Bugs

 * The cause is still unknown, but sometimes one or more of the Hardcore needs (such as H20, FOOD, SLP) will disappear, and will not even indicate a 0 integer. But you can fix it by going into the options then turning hardcore off/on again and that will reset all of your needs to 0. But this seems to be a redundant problem once it happens the first time, and starts upon loading a save. A way to fix it is to make a backup save, and delete the old file.
 * Another fix for the above bug is to use an item that increases/decreases the meter of said needs (i.e. of 0 integer is missing in SLP then take a nap and the integer will reset to 0).
 * If the above tips do not work the first time, you may need to initiate them more than once.
 * the unpatched version of the game sometimes glitches and stops players from leveling up though still registering experience.
 * If you transfer your save game to a new computer and continue playing, the Hardcore achievement may not register upon completing the game, even if Hardcore mode was never turned off.
 * The sleep meter will not go below 2.
 * Hardcore meters (H2O/Food/Sleep) may sometimes stop increasing in "real time." Sleeping, waiting, or fast traveling will still cause them to increase, though. Reloading a previous save can sometimes "unstick" the meters, but they tend to become stuck again after approximately 10–11 minutes of gameplay. No cause is yet known for this glitch.
 * Loading a save can sometimes cause the hardcore meters to increase substantially from their levels at the time the save was made, as if the character had waited after loading the save. Most noticeable with H2O, probably because it increases faster in-game.