This is an in-progress, evolving guide, intended primarily to help newer players (and possibly some more experienced ones, in some specific fields, who knows) and give myself something to do. If there's anything I got wrong, or some information ends up out-of-date, or there's something I missed (all of these are inevitable), please, don't hesitate to let me know. Do please keep in mind that all of this is incomplete, the guide will be expanded to cover more topics (such as individual bots, [and the flavor text in their CAM files], CNC crafting, hacking, ect.), and go into them more in-depth as time goes on (such as what exactly is on each individual CNC folder, and the exact damage of the EMP bomb in the Leech Bunker).

Good luck, happy hunting, hiding, and scavenging!

Note : As of July 9th, I've returned to the game to find there has been a pretty massive map change, deceptively massive, in fact. Roads were added.
I'd like to take a moment to point out just how much these roads actually improved the experience, in a really weird way. You see, before there were the roads, the game just felt like you were going between a few key locations, and the area between them was just kinda... Dead space, really. Nothing there, neither interesting nor particularly challenging - if you can't shoot it, you can avoid it without issue. Now, though, not only does the world feel more filled-in with the roads alone, but there are a number of little houses set up along them, sort of mini loot spots and potentially temporary player bases? Also, I blindly followed the roads and evenutally found myself at a location I had been unable to really pin down for the entire time I've owned this game, a little junk town that... Honestly, I might just call it junk town.
That being said, I'm doing a full rewrite of this guide - not going back and rewording or changing, just flat-out rewriting it. I don't know the proper names of all of the locations, apparently, and I won't refer to them by those names, either, more than likely. I make up my own weird names for everything, and if I get one wrong, don't be afraid to tell me - I'd be happy to change it.
As the final part of this note, I'll be adding a section at the end called "an awkward request". You see, I feel this game is still lacking on a few fronts, and I have some... Weird ideas, for anyone that actually knows how to do it. Essentially, it's a section for suggestions for mods (maybe?) and/or future game updates, because I don't know the first thing about coding.

First and foremost : You! And other players, I suppose..
You can modify your own parts at any repair station, as is mentioned in the tutorial. The parts you'd be trading out, you either spawn with, or can loot off of (primarily) other dead combatants - be they other players or AI.
That being said, these modifications make explaining a player's stats hard to explain, because what a character has and is capable of having depend entirely on their level and what parts they have gotten a hold of so far. The important things to know :

• The amount of power you can store is determined by the number of capacitors you have installed - not the amount that you're carrying.
  
• The rate at which you generate power is determined by the number of solar panels / nuclear reactors you have installed - not the amount you're carrying, even though carried + uninstalled nuclear reactors still give off radiation (though less than when they are installed).
  
• The rate at which you use power while moving is determined mostly by the amount of weight you are carrying. Carry weight will also determine how high you can jump.
  
• While damaged, the rate of power consumption from movement increases seemingly exponentially.

Second, your scavenging, tanky friend, the Harvester!
For the most part, Harvesters are just kind of... Around. You see them pretty often in the sky, and they can be useful as a pathfinding tool if you get lost somewhere you don't recognize. Following a moving harvester will always lead you either directly towards or away from the Nuclear Plant on Countryside (away if they're moving towards a resource deposit, towards if they've just finished gathering resources). Now, in my experience, Harvesters tend to be unstable. They are able to be destroyed, though it takes quite a lot. But the issue is that the resource they're gathering can be very hard to control, as they have a tendency to overwrite your commands. Put simply, it takes a careful series of inputting commands and turning it off and back on again to get a Harvester to follow your orders properly.

Third, we have the ever-present and only occasionally terrifying Detonators!

The fourth combatant in the ring is the Hunter, an AI that varies wildly both in and between updates.

Fifth, we have the Swarmers. I'm pretty sure these are the things that caused a "divide by zero" error.

And bringing up the rear, we have the Leeches. Where do they come from? No idea how they get on the surface, but they do, sometimes.

It is rumoured that in the future, there will be multiple arenas. For now, though, there is only one - referred to as Countryside. When another map comes out, I will happily begin trying to hunt through it for anything and everything I can find.

Countryside has two bunkers, both of which are only available to access in Singleplayer, to my knowledge.

Trying to upgrade yourself can be dangerous, especially alone and if you have no idea what you're doing. It's suprisingly simple to take off your leg trying to add a power source and forget to put it back on.

This is something that gets fiddled around with quite often, as a player. Earlier on, you're constantly creating, dismantling, and upgrading your various weapons to suit your needs and supplies - only have one grip, but three different slides, and ammo for two of them? Not a problem! Soon enough, you'll realise that your one grip might fit all three, so you just make one, use all the ammo, dismantle, and reassemble it for the other weapon!

Now, I lump these together simply because hacking is short, sweet, and covered in the in-game tutorial pretty much in its entirety, and because I don't exactly understand the construction mechanics all that well. It's a bit of a funky physics engine, makes raised structures have randomly exploding supports, last time I checked. Then again, right now, "last time I checked" was before roads were a thing, and when Leeches were spawning glitched into player-constructs.

Now, this game is a tad... Lacking, in some regards. As it stands, I can only really recommend playing this game online if you have friends to play against. I put emphasis on against because, in my experience, team-playing is a very short-lived experience, unless you're playing for base-building and next to nothing else. In which case, you still might find yourself coming up short, at the moment.

There are just a few changes I'd like to request. Not changes, perhaps, but additions.

1 : Enemy AI
This is actually both a change and an additon, and almost certainly the hardest one to deliver on, I'm sure. As it stands, there are two issues with enemy AIs, which I will go over separately.
1a : Difficulty. This is more in the way of the Combatants, themselves, than the AI that governs them. Essentially, if you see the enemy coming, you end up in one of two positions, depending on what point you're at in the game. Either you don't have a weapon that can let you deal with them, so you simply go around them (which is excessively easy, in most cases), or you have a weapon and enough ammo to deal with them with ease. Swarms and leeches almost always fall under the prior (being so easy to avoid and relatively difficult to hit), with detonators and hunters making up the latter whenever you have a ranged weapon. Now, where exactly this divide comes from is a matter of debate - I know that early-game, one hit from anything means death if a second hit is in the making, simply because the first jacks your movement's power drain so high you can barely walk, unless you're hit by a Swarm. Still, though, I feel there needs to be something to bridge this divide - and more importantly, something that isn't a breeze to avoid, even if it isn't the largest threat.
1b : Intelligence. This is a thing with the AI. For one, Leech AI has a tendency to get stuck on structures and walls - both player-built and ones that are part of the map. Also, Swarms.. I mentioned a "divide by zero" error in Combatants? That wasn't a joke. There was a swarm that tried to fly through the parking-complex-like structure by the power plant. It got stuck on the underside of the first floor, unable to move. Suddenly, it glitched out, flew up through the structure, flew around for about two seconds, and then just exploded. A second came by and got stuck, as well, and my game crashed with a divide by zero error. I'm assuming there's something in the code that divides by the Swarm's height above the ground? But I digress. When things don't get stuck, like the Leech and Swarm, they have this awkward issue with noticing you. Detonators will blindly walk around you - generally to wherever you were about 5-10 seconds ago. This is a neat little detail, sure, but it means that hacking them isn't an issue, since their movement is so slow and delayed. And sometimes you can beat a hunter to death with a bat before it turns to notice you. It's just a set of weird issues with pathfinding and movement, really, and it makes them really, really easy to avoid.
One big note that could help adress both of these : Hunter's don't one-shot, anymore. As a matter of fact, their overall damage dropped massively. My vote goes for simply giving them better aim and detection AI. They're called Hunters, after all, let them hunt! Maybe in the future they canemploy some sort of dog-like robot with particularly fine-tuned tracking tech. Let it be loud and proud. If you're really daring (maybe make this a difficulty setting), you could give it a roar with a massive power drain effect - calling all nearby hunters to a located player (temporarily increase hunter movement speed?) and making it more difficult for players with higher power needs (high carry weight) to get away.
Of course, this would probably go against the lore - after all, what kind of purpose would this serve in the pre-apocolypse? Besides maybe hunting down old rogue AI, if that was an issue. Still, it's an idea worth keeping in mind to build off, hopefully.

2 : Construction. At this very moment, take this one with a grain of salt - I'm just writing this out while I can still remember it and put it into words, properly. I'll be doing some playtesting to see if it still holds up.
This, as well, has two issues, both of which can be described much more quickly than the last ones. As I mentioned in the Construction section, the physics engine is a little... Funky.. It can be difficult to build a lasting, ranged structure, as the weight of it can randomly cause certain supports to randomly break. Those now-gone supports puts more strain on other supports, causing those to eventually break, and so on. Personally, I'd recommend something along the lines of a 7DaystoDie approach, where each item has a weight and load capacity, listed somewhere. Even if what's supplied is abstract and arbitrary, we, as players, can still then try to piece together what an effective building ratio is, in terms of load and weight, even if it's not nearly as simple as 7Days' is (and it really shouldn't be, either. I get the feeling that the current system is actually, fine, I just.. Don't understand it. There's no values to work with and base everything off of, so it's just kinda blind trial-and-error)
The second part of this issue is variety. Now, this isn't a huge thing, it's just me nitpicking, but it is something I have a bit of a problem with, just because I've been playing alone for so long. See, you have the base building blocks there, sure, but there's a little bit missing, still. I guess, all I'm really after here are things like half-walls, manned turrets, windows, ladders, hatches, things like that. I'd like to go out and build destructible arenas, ya know? And that gets a lot easier when pieces like these are available - half-walls could be carefully done with either pillars or walls half shoved into the ground, sure, but it's then either a massive resource drain and/or it doesn't necessarily look as nice.

One last thing : with how touchy and weird building can be, might I recommend a "temporary frame" option in the fourth schematic drive? So, for example, one wood could make a temporary, full-box wooden frame. Large enough for one floor tile to fit in the bottom, and if you connect a bunch of frames together, you have a temporary building block, sort of. It's a little hard to explain, I suppose. Each frame is one section of building. The frame offers no structural integrity for anything besides other frames, but it's something that could let you see how a construct might look before you go all-in, and look at what supports you might need, where, and build them perfectly in place, ahead of time (you can replace the corners of the frames with supports, so that everything lines up perfectly, and easily)