Independent
The camp
You can shave quickly in the camp, but it won't be the high quality job you would get from a barber in the city
The camp needs money, food and supplies
If morale is down, one of your gangmembers might ask you to go to a bar with them from time to time
We know that you don't need to keep the camp fed and happy, but there will be upgrades to for doing so and hidden benefits. We know that it's not a must to do so, but it will pay off if you keep the camp happy. It doesn't state what type of upgrades.
Interactions
A farmer will behave differently from a sheriff, so different types of people have different types of interaction "branches" that could play out
These branching options also comes into play with your horse, and with dogs as well which you can choose to praise or scold
Weaponry
Weapons are open to an insane amount of customization
Rifles can have their metal types changed
Handles added or removed
Can be engraved
Weapons also must be cleaned regularly and they will degrade over time. So that mean you need to repair your weapon.
Horse
Needs feeding, grooming and you need to calm it when it gets scared
Certain horse breeds will be faster than others, but they can be more or less comfortable in certain types of terrain and react to gunfire differently
You gain speed slowly appearantly and the horse doesn't go from a dead stop to a full gallop in 1 second
Honor - This will be something that affects how other people in the game threats you. - Who you choose to be in the game will affect how it plays out
Venture Beat
General
Animal cruelty is a crime so if you shoot a dog and someone sees you do it, they will tell the local sheriff.
If you get a bounty on you and you get killed, the bounty is still on you. So you have the choice to pay that bounty at the post office
If you get shot and killed, you will discover that your clothes has bulletholes in them.
So if you come back to that same town, people will remember what you did and make a comment, even though you are carrying your weapons holstered.
Arthur was adopted by Dutch as a child and he grew up in the gang
Horses have unique personalities and abilities
The horse can carry weapons and inventory
Weapons can jam or misfire if not maintained and cleaned
Different types of ammo, each with different effects
Your clothing affects your stamina, particularly if you are not dressed for the weather.
You can decorate the handle on your guns.
There is 5 levels of Dead-Eye in the game and you earn those throughout the game
Dead animals will appear as paw marks on the minimap so you can locate them. Dead humans will appear as an x on the minimap
There is legendary animals and you can hunt them, and then deliver the pelts to a trapper so he can make a rare clothing for you. There is only 1 legendary animal to select species.
You can also come across famous gunslingers who are listed on cards as the best shooters ever. You can collect these and collect them like animals. I'm not sure this is actual people you can hunt down or if this is some kind of collectible within the game.
The camp
If you walk near a group of people they will naturally included you in their conversations and when you have walk away they will ignore you
The gang is aware of the activities as you play as Arthur and activities they have been a part of. Example: If you are robbing a train with some gangmembers, they will talk about it if you visit the camp later on
Press Start
General
You can wash your cloth if it comes in contact with an animal carcass. I will also say that it works the same with your horse too, if you put an animal carcass on your horse there will be blood on the back of your horse. This can be washed away if you walk in deep enough water or being in the rain.
Horse
You can own more than 1 horse so you can have back-up horse if the horse you are using gets killed
Bonding with your horse grants you benefits like being easier to handle and unlocks skills like rearing(backing up?) and doing skid turns while galloping. Skid turns is sort of like a handbrake-turn with your horse.
Arthur
Arthur needs to be maintained to be healthy
His beard and hair will grow as you play and you can cut, shave and style your beard and hair as that growth occurs.
If you don't eat, you will notice Arthurs arms getting skinnier
If you overeat, Arthur will get fat
If you let your health and stamina bar drop too low, Arthur will become dizzy and dysfunctional
Interactions
Citizens will interact with you differently based on how you look. Like if you go around with bloody or dirty cloths, people will treat you differently than if you were walking around with clean clothes
This will affect the different types of interaction options you will be presented with
VG247
Shotguns allow you to blow peoples heads, arms and legs off their bodies!
Dead-Eye can be upgraded to...target vital organs!
This works sort of like an X-ray vision where weak spots on the enemy is glowing, allowing you to go for the heart or other killshots like lungs or the brain. This also works on animals to let you kill the animal faster.
When you land an impressive shot you will get treated with a slow-motion cinematic camera view of the bullet to the target before putting them down. This is triggered contextually and takes into account accuracy, distance and other factors
You can fire warning shots in the air to scare off wild life and to attract the attention of NPCs
If you shoot without aiming, you hip-fire and if you do that with a single revolver you can see Arthur fan the hammer - which means shooting really fast
Here is a weapons guide and contains more information than the article posted by OP.
Arthur is limited to the number of weapons he can carry on foot
He can carry 2 side arms, 2 rifles or a bow and a rifle on foot
He is also armed with a hunting knife, throwing weapons and a lasso
However, when you are near your or on your horse, you can pull up a full inventory like a weapon wheel to choose what weapons you wish to carry while on foot
When shooting with a bolt action rifle you need to tap a button to load the next bullet
The weapons will degrade if not looked after
Which can affect firing, reloading and recoil
The amount of use, the environment and any modification are also taken into consideration and can affect how the weapon handles
If you travel through water, the weapons can rust
Firing the weapons without having cleaned them will build up dirt and slower your firing rate
You can inspect your weapon to check out it's condition
Weapons can be customized with engravings, leather straps and more
Players can buy or craft specialist and everyday ammo to improve range, damage and recoil
You can do close-range takedowns with your knife or bow silently killing enemies
Game Reactor
General
If you search through drawers and chests or anything and you find a letter or notes, you can examine that and might find useful or secret information
You can move your horse sideways at will
If you stand still with your horse and hold square(PS4) or X(Xbox) the horse will strafe in a given direction. Meaning you choose which direction.
NPCs remember you and can greet you. Example: If you fight someone in Valentine for instance, and you come back days later and visit the gunsmith, he might discuss that specific event with you.
Polygon
General
The weapon system works like in Max Payne 3. Personally, I'm not familiar with this, but after having read through all of this I'm pretty sure what it's about.
Dual-wielding is something you have to unlock
You can take out your gun or holster your gun with L1(PS4) or LB(XBOX)
Your horse can become skittish in stressful situations. Example: If you are walking along and you come across a snake, the horse will stop moving in the direction of the snake. I also want to add that walking with your horse in bad weather like thunder and lightning will make your horse agitated.
XboxAchievements
General
Bodies can be looted for weapon parts to upgrade your arsenal or treasure maps
I know I have mentioned this, but your weapon can be customized. The length of the barrel, the type of metal the cylinder and hammer is made out of can be customized.
Stealth is a viable option now. You can carry out coordinated attacks with your fellow gang members as well.
If you fail to maintain Arthurs health, you can become so weak that you can drown when swimming
YOU CAN SWIM!!
Clothing comes in individual pieces so you can mix and match clothes to look just how you like it
Just like Arthur, your horse needs to eat and rest to not get weak and skinny.
You can visit the local sherrifs office and take on bounties
Train robberies are not restricted to story missions
This is a repeat, but this site also states you can blow peoples heads off. So this is the second site that has said you can shoot peoples heads off. "The proof is in the pudding(pun?)when I managed to blast one hapless bandits head into a grisly pulp."
Forbes
General
If you fall in the mud, like in the gameplay trailer, and walk off and spend time in the sun, the mud will become dry and it will cake.
Horse testicles waggle as you walk and they shrink in the cold