You shall never encounter a Radscorpion or Sentry Bot.
Mr. Gutsy rocks.
Fallout 4’s New, More Challenging Survival Mode Explained
Fallout 4 New Survival Mode Overview
Saving
Manual and quicksaving are disabled. To save your game, you’ll need to find a bed and sleep for at least an hour.
Combat
Combat is more lethal for everyone. You now deal, but also take, more damage. You can increase the damage you deal even further with “Adrenaline” (see below).
Fast Travel
Fast Travel is disabled. If you wish to be somewhere, you’ll have to physically travel there.
Weighted Ammo
Bullets and shells now all have a small amount of weight, which varies by caliber. Heavier items such as fusion cores, rockets, and mini-nukes can really drag you down.
There’s more ... http://www.gamespot.com/articles/fallout-4s-new-more-challenging-survival-mode-expl/1100-6435071/