In Radfall, the player has a lot more health, and combat should not generally feel super lethal. Horizon players should be familiar with this strategic resource-based rather than tactical balance approach. The sweet spot Radfall tries to hit is that you can get through most encounters without dying, but you do have to use healing resources, and you need to prepare for difficult encounters. This is specifically to fix the tactical respawn-until-you-get-it-right style gameplay vanilla survival has.
Sneak Attack no longer grants bonus damage unless you have perks, and the stealth meter is hidden by default. Stealth isn't the cheat mode it is in vanilla.
Food can only heal you up to the segment thresholds in your health bar- if you lose an entire segment of health, you need a stimpak, a medpak, or a doctor to get it back.
Drinks now grant AP buffs, instead of healing.
Commando grants the chance for extra ammo with automatics, if you want to spray bullets, you're going to need it.
Weapon crafting works a little differently in Radfall. Some basic customization is still available, but finding the perfect base weapon is more important.
Attachments (mags/scopes/muzzles) are swappable- just pull it off one weapon, and put it on another
Pipe class weapons are more customizable. They have lower perk requirements, but they deal less damage than pre-war weapons of the same caliber.
Recievers are crafted with Weapon Scrap that is obtained by scrapping weapons (make sure to pull off any attachments you want first)
Weapons that have degraded will have an extra "repair" recipe available to them that allows the player to craft a replacement reciever even if they don't have the perks normally required.
The economy in Radfall is based primarily on trade, not on currency.
Don't expect to accumulate caps by mindless vacumming up all the garbage you see and dragging it to a vendor.
Look for items with high value and low weight (e.g. Cigarette Packs are a great example of this), and use them in trade when you want to buy an expensive item.
Vendors have significantly fewer caps, and there are no ways to increase the amount of caps they have.
If you want caps, then you have to go find them the old fashion way: ask for a quest.
Vendors will typically only buy items they're interested in selling. E.g. weapons vendors aren't interested in buying your chems anymore, you'll need to find a chems dealer to offload them.
Keep your eye out for unique food items at vendors, eating them can unlock a new recipe.
Crops have a lower harvest rate, don't expect to get something every time. If you want fruit and vegetables to cook with, your best bet is to build up a farm with enough extra production above and beyond what the settlers require that they'll leave some in the workbench for you.
Cola and other drinks are great for a quick AP boost, but no longer heal.
If you haven't used True Perks before (which Radfall is built on top of), don't worry too much about specials at character creation, just put something in, and then after you get the pip boy, spend some time looking at the perks, find a few you want to try, and rebuild your specials around getting them before exiting the vault.
There is a purchasable perk point respec called "Mindwipe" that will allow you to reset your invested perks, but it won't allow you to respec your specials, it's a rare item available at chem vendors.
Because "required" perks have lower requirements, pretty much any build is viable, as long as you have a good mix of offense and defense.
There are no safe "dump" specials. Putting a 1 in any special will have drawbacks.
Specials can be trained past 10.
Special training perks now have a level requirement- you can take the 1st rank at level 7, the 2nd at level 14, etc.
Settlement crafting in Radfall is designed to be mostly hands-off, every settlement item that doesn't have a purpose has been disabled (although these are toggleable with an MCM)
Many settlement items now require specific pieces of scrap, these can be found in the world or purchased from vendors.
The player can run while over-encumbered, but it drains AP, and it drains more AP with your weapon drawn- so keep it holstered while over-encumbered.
Instead of getting 10 carry weight per strength for free, Backpacks/Pocketed armor mods now grant you 10 Carry Weight per Strength (up to their total bonus carry weight).
Over-encumbrance now damages your fatigue (the penalty to your AP), instead of your limbs and health, based on how much you are carrying.
The overall effect of these changes, is that encumbrance isn't much of problem outside of combat.
Dogmeat doesn't count as a companion for the Lone Wanderer Perk
Companions heal themselves (assuming you've loaded the default MCM settings), and don't need to be stimpacked/repaired when they go down in combat.
Companion weapons can be upgraded by equipping them with a weapon of the same type
Companions have significantly reduced carry weight.
Survival disease is completely disabled. It is a poorly implemented mechanic that distracts from the core gameplay loop of exploration.
While there are no camping mods included, Sofa Surfing will let you sleep on any sofa or armchair.
Adrenaline is disabled. It's a weird, unintuitive mechanic with no player feedback to let you track how many ranks you have, that they added to the game to make up for the huge damage nerf they hit the player with in vanilla survival. We've removed that damage nerf, so the mechanic no longer makes sense.
As long as you have the locksmith perk of the required level, Lockpicking can be bypassed (althouth this costs a lockpick)
Hacking can be bypassed with Mentats, as long as you have the hacker perk of the required level.