I don't know if it has already been suggested, but i find the survival mechanics from the game " the long dark " immersive, especially on the food / water part. Aswell when you're hurt, you need antibiotics, painkillers etc... plus the cold gestion, who's not necessary on fallout 4, but imo it's pretty good. A " matchup " between fallout and this game, to add a survival way with a better realism could be fun !