MG Survive does a really poor job, in explaining all the game mechanics properly and how to actually get many things done. This guide aims to fix that by explaining everything the game does not, or does in an incomplete way.
Guide to Unexplained and Hidden Mechanics
Section 1: About Items, Containers & Resources
The game explains that Containers can be opened in two ways: by lockpicking them, or by breaking the lock. There is also a third way: if one fails the lockpicking minigame, the lever becomes red but can still be slowly pulled to the end, making a great sound that will attract enemies in a large radius. However, the container will open eventually and reveal its loot normally.
Containers will reset, become closed again and spawn loot again after some time. How much time exactly is not clear, but it's not less than 24 real life hours. So every 2 real days, go and check previously opened Containers (remember to mark them on the map with the stickers) - they will have more loot to gather.
Respawned Containers (mentioned in the previous point) will have different loot than the first time, each time past the first opening. They will not award any more Blueprints or otherwise special items, but will instead always award Material, Weapon or Gear Cases, which can eventually award random Weapons or Gear to restore at the Workbench.
Resources gathered in the world such as trees to chop to get wood, gunny sacks, tires, iron barrels... anything you can actually pick up or destroy basically will respawn after some time, enabling you to gather it again. This is valid for all resources including non-event animal packs (wolves, sheep...) and herbs, they will respawn where you first met them after some time, exact spot.
The time for this to happen is around 4-6 hours of playtime, i don't know an exact timer, and also happens when the daily quests refresh (so every real life day). Make a "tour" or locations with a lot of resources (such as teleport bases) each day at least once, to gather a lot of resources without risk and quickly.
"Strong Kuban Energy Reaction" events tend to spawn near the location of undiscovered Containers. Yes, I made tests about this, and it's true: the game uses this specific type of Random Event to "guide" you to a lot of undiscovered containers you did not open the first time yet. The containers are usually near the area where the event takes place. This is NOT a rule for 100% of containers, but for most it will happen. So if you see "strong kuban reaction" event, go have a look.
You can convert materials into other materials. For example, you can make Concrete [Rare] from Cement [Uncommon] and Stone [Common]. This applies to all materials you have discovered: each has a conversion recipe you can use to obtain it from other materials. To do this, go to a workbench and select the option "Convert Materials", a list will show all the materials you know, and how to make them.
Exceptions: this process cannot be made to create organic harvested materials or special items such as animal skins, specific types of animal parts (such as "Striped Wolf Pelt" or "Bear Paw" for example), same goes for Herbs, in these cases you must harvest that specific animal or plant to get the material. But for all the other ones, it works.
You can extract animals and enemies with the Wormhole Transporter for different bonus effects. In the case of Enemies, they will yield 50% more Kuban than regular harvesting, and it's also faster. In the case of live animals (Not animal corpses, those cannot be extracted this way), they will give the same materials but if you have a cage in your base (like the Goat Cage) they will instead be captured alive, and provide their materials over-time as a Harvest resource.
To do this with an enemy, you need to kill it with a Stealth Kill OR kill it by shooting the weak point on their backs (a little bit lower than the neck). After this the enemy will convulse on the ground for about 10 seconds, you have this time to extract him by holding Space down near it.
To do this with a live animal, the specimen needs to be stunned on the ground. The easiest way to do this is to start sprinting fast (hold down Shift) and then perform a Sprint Punch (left click while running) on the animal - this will knock on the ground any Small and Medium animal (Goats, zebras, donkeys...), after that press and hold Space near them to send them to your base.
Exceptions: Large Animals are too big to stun with this method, so they cannot be extracted via portal. Some enemies cannot be extracted, generally those with a non-human shape. Those with a humanoid shape usually can. Also, this doesn't work with Birds, Rats, Gerbils and similar things because there is no way to stun them without killing them.
Section 2: About the Base Camp
You can gather a small amount of resouces and most importantly clean-up space, by dismantling the rubble piles present around the base camp's area. To do this, enter Bulding Mode and then select the "Move" option from the menu above (the one with 4 arrows icon). With that selected, hover the pointer over one of the rubble piles, and you will be able to dismantle it as if it was a structure.
If you want to free up a Goat Cage (or any animal cage) to put inside a different type of Goat (or other animal), then dismantle it and rebuild: the goats or whatever else will be gone.
Any defensive buildable item gives its defense power to one of the 4 colored zones of the camp, depending where it's built. If an item is put in a square where two different colored zones overlap, then its defensive power will be split 50% in one zone, and 50% in the other.
At a certain point in the story, the game will tell you about a certain time limit you have to consider. This is however not true: this time limit will not be real, and even if more time than described passes, the event will not occur until the main story mission has progressed more. So, take your time.
You can engage in co-op Salvage Missions alone, as they do not necessarily need other players, even if they're called "co-op". To do this, access the Staging Area by talking to Virgil (the computer) at the Base Camp, then set the match type to Private and select the level: you will be able to start alone. The difficulty and enemy numbers however, will not be different, so it will be ever harder as you will be alone.
The maximum stack of an item produced by your Base Facilities, such as the Water Collector, a Potato Field or Goat Cage is always 10 Units. So for example, a Water Collector cannot contain more than 10 units of Dirty Water for pick up at the same time - after that it will not produce any more water you can pick up yourself. So remember to collect it every once in a while, same for all other things that yield materials in this manner.
If you're not sure when the game last saved, you can use one of the Tents or Shelters in your base camp to sleep 1 hour. After this the game will always save.
Section 3: About Gear, Equipment, Vehicles & Weapons
It is possible to equip multiple arrow types at the same time on any Bow, and switch them when needed. To do this you need at least one "Quiver", and also at least 2 different types of Arrows. First of all equip the quiver in the Gear menu, as it occupies one Survival Gear slot. After this, go in the Weapons Workbench and select Change Equiopment, then go to the Ammo tab (the one with bullet icon): there you will be able to select what type of ammo goes where.
To have multiple arrow types, put in the Quiver whatever type of ammo it is designed to hold (Example: Heavy Arrow Quiver will only hold Heavy Arrows), then in the bow itself (which counts as a separate arrow container) you can put any type of arrow, but only 20 of them. So for example you can have 30 Heavy Arrows in the quiver, and at the same time 20 Flame Arrows in the bow "magazine" itself.
To switch arrow types, press down and hold the button assigned to select the Primary Weapon, make sure the Bow is highlighted, and then while still holdiong it down press Q or E to swap arrow types. You will see the Captain do an animation where he/she fiddles with the arrows a bit, and after a couple seconds you will have the other arrow type selected to shoot.
All vehicles such as the Jeep or the Walker Gear degrade over time by using them, and their ammunition cannot be reloaded in any way. However, the degradation occurs only if the vehicle is used for moving, not shooting. So, if you use a Waker Gear's minigun but stay still in one place, the degradation will not progress.
To throw grenades, lures or anything else a lot further, you can press Space to change the throw type from Underhead (default type) to Overhead. After doing this the throwing arc will change and become longer, allowing much more distant throws.
Reinforcing armor is useless. It only slightly upgrades the Durability value, while Armor value stays the same. There is no actual improvement whatsoever in my experience. So don't waste your Kubans and Materials on this. Weapon improvement is, instead, quite good and worth the effort.
Gear and Weapons crafted from "Broken" stuff found in Cases always has at least 1 or more special attributes, and cost about the same to craft as regular ones. The attributes also will be already unlocked and ready to use (on normal equipment you have to consume extra resources to unlock them). So when possible, use "Broken" gear as a base to craft your weapons or armor, instead of normal blueprints: the result will be comparatively better because of the special passive skills.
Section 4: About Combat, Enemies & Fight Mechanics
Spears are the only melee weapon category that can attack through fences. Despite what the fence effect says [Attack Penetration: attacks can go through and hit enemies behind], other melee weapons will not go through. Only spears.
If two enemies are close enough to each other, a bow attack may hit both of them. This applies to Normal and Heavy arrows. If you see two or even more enemies clipped into one another (usually happens when they're attacking a fence or wall), there is a decent chance the arrow will damage more than one when it hits.
Grass on the ground creates large fire areas in certain conditions. When you hit an enemy with a Falme Arrow or also a weapon that inflicts Flame damage, the enemy may catch fire. If this happens while the enemy stands on a dry grass patch (like desert grass), this vegetation will catch fire and become a large patch of flames. The patch of flames will inherit the damage over time of the source, so for example if a Flame Arrow does 25 damage per second as Burning, the same will be for the fire patch.
Wooden Walls, Barricades and similar constructions will not catch fire if struck by fire damage, despite being made of wood. So don't be afraid of this happening.
Heavy Special Attacks will always stagger normal Wanderers and even Trackers if they connect, interrupting whatever action they may be performing, including attacks. This type of attack needs first to be unlocked as a Skill, then you need to press R while holding down right click (readying weapon). This will perform a different animation based on the weapon category.
The important thing is, that normal attacks have a chance to stagger an enemy, but they also may not do so, it's random. In my experience Heavy Specials instead always stagger no matter what. This does not apply to Bombers, Mortars and larger boss-type enemies, stagger on them is not guaranteed even with Heavy Special.
You can melee-counter a Tracker's jump attack. You need to have the Counter skill unlocked to do this, it's in the Survivor skill tree (base class). The interval for pressing left click and perform a counter is very small, but if successful will grab and throw the Tracker away, knocking them down and making them vulnerable to whatever following attack or stomp.
If an enemy has a red name with a red skull near it, that means that enemy is too powerful for you at the moment. You will cause reduced damage on it, and receive bonus damage from him. In cases like this, just get stronger and go back to that area or event later.
Bombers will not explode if killed with a Stealth Attack or killed with a critical hit to their weak spot in the back of their bodies. Also, Bombers will not explode when attacking a Decoy. They will keep trying to melee it as long as it's there, but never trigger the explosion sequence.
Section 5: Other Mechanics & Workarounds
Metal Gear Survive does not tolerate well the practice of Alt-Tabbing. As you may know, pressing ALT+TAB on the keyboard will minimize any fullscreen application (such as games) and allow you to use the desktop for other things, such as googling something for example.
This game does not react well to this, and it may even trigger disconnection that will kick you back to the main menu. It happened to me a couple of times. So avoid Alt-Tabbing to be safe. If you need to google something, activate the Steam Overlay and open the Web Browser by clicking "Web Browser" on the bottom left - it will allow you to surf the internet without Alt-Tabbing.