Radaway heals radiation poisoning instantly. In addition, recruited companions can die permanently. Sleeping does not heal health points or crippled limbs, unless it's in an owned bed or having the Roughin' It perk. Limbs can only be restored by a doctor's bag, hydra, weapon binding ritual, healing poultice, Auto-Doc, or by visiting an actual doctor. In this mode, stimpaks and other healing items heal over time instead of instantly, RadAway removes radiation over time in a similar manner, ammunition has weight, and the Courier must stay hydrated, eat periodically, and have a regular sleep cycle.
It can still be turned back on, but the achievement/trophy will be unobtainable. Hardcore mode can be toggled off at any time through the options menu.
The mode is initially available just before the player character leaves Doc Mitchell's house for the first time and they are given the achievement/trophy for keeping Hardcore mode on continuously from this point until completing the main questline. The achievement/trophy is awarded for completing the game from start to finish in Hardcore mode.
