1.Weapons
There are many weapons.
As far as i know there are 2 Shotguns, 2 revolvers, 2 pistols, AK-47 and Lee Enfield or Nagant Mosin, idk how its called.
2.Ammo
Both Shotguns use same shotgun cartriges.
Each Revolver uses different ammo, there are bullets for magnum and different type of bullets for default revolver.
AK and Lee Enfield/Nagant Mosin uses the same ammo, i never had ak or lee enfield before, but they use pretty long bullets.
3.Trees
You can cut down trees, apply gasoline on tree, fire it up with lighter and you can raise ur body temperature.
Also, you can build bases. If you have wood in your inventory, take hammer and double-click on wood, everything else you will figure out yourself.
4.Cars
As far as i know, there are 3 cars.
UAZ, VAZ and Tractor.
To drive cars you will need-
Jerry cans with gasoline and battery/accumulator.
5.Weapon mods
You can apply several mods on each gun.
All i know about is flashlight.
You will need flashlight and battery, insert battery in flashlight.
Ductape the flashlight and it will automatically appear on your weapon.
You cant use red dot sights on both shotguns.
6.Secrets
Sometimes you can find keys and go to the secret rooms, i know only one secret room, its located on 2nd floor on School, there will be a ladder to attic, to open attic doors you will need a key you can find somewhere on school.
7.Bags/Clothing
You can find bags, bigger bag gives you more space for food, drinks etc.
Im not sure about this one, but if you have bigger clothing you can get more space on your inventory. i noticed that after i picked smaller jumper than i had, i lost some space on my inventory.
8. AI/Dogs
Dogs attack you, but after new update some dogs are just sleeping and they won't do anything if you go near them.
If you kill a dog you get meat out of him, you can eat it, but to get better effect, you can bake the meat simply by throwing it on fireplace.
9.Healing
If you fell down from high place and you are wounded, or dogs bite you, you can use bandage to stop the bleeding, use pinicilin and vitamins.

Thank you for reading, rate it if i helped u out! As soon as i will find out something new i will edit this guide, i hope this guide helped alot.