The world of Fallout 4 is a grueling one. From being chased by Deathclaws or getting mauled by ghouls, there's already quite a bit of challenge within the basic, vanilla version of the game itself. However, Bethesda didn't want to just stop there, which is why Survival difficulty is an official feature in Fallout 4. This difficulty turns the game into a full-on survival experience, with real stakes and no manual or autosave. Players can only save when sleeping. Moreover, the Sole Survivor will be subjected to thirst, hunger, and exhaustion.