If you feel anxious about the "doom clock", this is for you:
Don't worry about it! ...too much.

In the beginning, the population seems to be falling frighteningly fast - You research the population census and it's already at 95%. Next time you look as you have your first missions with countdowns it's at 87%... 82% a short while after, how can you possibly finish the game before it hits rock bottom, right?

Let's look why it is so fast in the beginning and why it will drop so much slower later on:

1) Starvation.
All havens start with considerably more people than they can feed, and starvation rate is probably some sort of exponential function or linear interpolation where it drops by X% of the surplus each day; the closer the number gets to what the haven can support, the slower it will drop, flattening out when population drops down to a sustainable number.

2) Havens you cannot even see may get destroyed; there are more than enough of them and you will get more agency later on.

3) Perception of time-flow.
Initially, there's a lot of waiting where you just let the clock run at high speed. Exploration of (?) take 4 hrs each; maybe you wait for a research, maybe you wait for a team to heal.

Later you may find that only low stamina causes you to rest since you'll use medpacks more often; being cheap on them and letting the clock run instead is a bad deal. Later even, with the Festering Skies DLC, stamina ceases to be a problem once you put hibernation modules on your aircraft.

The in-game clock runs less and less as you progress: when you get more teams and fewer question marks to explore, fewer days will pass per hour you play the game. You'll have more and faster aircraft and you'll do a lot of missions which don't progress time.

4) You get more agency over time to help havens out by defences, supporting faction research or (if you chose to) repairing damaged structures like razed farms. You'll actively protect people from getting killed instead of just wringing your hands.

I have finished one game on rookie (prior to the ambrose update) and two on veteran after the update (with festering skies) and the meter didn't even drop below 65. The two veteran games I've played ended at a solid 70% +/- 1 or 2 points. In the last 2-3 weeks of game-time there was barely any movement of the census at all. Of those 3 games, the longest took me about 100 days, the shortest 2 months + 2 weeks.

Your operatives are exhausted at 0 stamina, tired at 10 and below.
Going into a mission with 11 stamina is perfectly fine, no need to rest every mission just because there's an exclamation point next to your operative's stamina bar.

...and why the Bulldog is an actual upgrade to the Ares
As the loading screen tip says: armour reduces damage by the armour value, a 50 damage shot hitting 30 armour will inflict 20 damage.

In all examples, it is assumed that all bullets hit the same body part.
The easy one that leads to the familiar misconception that the Bulldog is a downgrade:

0 armour:
- Ares hits 6 times for 30 = 180 damage.
- Bulldog hits 4 times for 40= 160 damage.

Seriously, how often do we see 0 armour... how about
10 armour:
- Ares hits 6 times for 20 = 120 damage.
It also applies 1 shred with each projectile, and I believe (maybe wrongly) that shred is applied after the damage is dealt. So the 2nd projectile hits a 9AR target and does one point of damage more and so on.
Additional damage due to shredding would be 1+2+3+4+5 = 15 which brings us to a total of 135 damage.
- Bulldog hits 4 times for 30 = 120 damage and applies 2 shred per bullet.
Additional damage = 2+4+6 = 12 which brings us to 132 damage.

Fairly early on you'll already see targets with 20 and more armour, lets run the numbers:
20 armour:
- Ares 6 times 10 + 15 = 75
- Bulldog 4 times 20 + 12 = 92

35 armour:
- Ares 6 times 0 + 0 = 0
- Bulldog 4 times 5 + 12 = 32
2 bursts of this might just be enough to disable an arm and take the enemy from the board if he only has a 2-handed weapon.

Shredding more armour leads to compounding effects, and after a few bursts this can make the difference between a virus rifle or paralysing pistol to apply their status effects or doing nothing at all (say, on a Scylla or late-game Siren). They need to be able to do at least a single point of damage to apply their effects.

Think of it like this: the advantage of B vs. A in the 20AR example is ~23% more damage
( (92-75 ) / 75 = 0.226...). If you were playing a RPG and found a sword that deals 23% more damage than what you have, would you take it or throw it away?

HOWEVER: the accuracy of the bulldog is lower by quite some margin, keep that in mind. You'll have them mainly on assaults, use their dash to get into position.

In the beginning of the game, with just a single fabrication plant, it takes 4 hrs to make a single frag grenade.
If you have nothing else to produce, make some grenades until you have a dozen or so, you'll need them against the pure for example. Frags do more than you might think, explosives damage (and shred) all body parts they hit, often both legs, torso and mayhaps an arm or any other combination, reducing armour on all these parts.

Oh boy

Cover in Phoenix Point is NOT an indicator for any form of mathematical defensive advantage. You don't get damage reduction by some percentage, your enemies don't get an accuracy malus of X points.
If your enemy (technically, your enemies' weapon's muzzle) can see you, he can hit you, it's as simple as that; this game is based on line-of-sight and the trajectory of individual bullets from the bad end of his gun right into your eye socket - if that path is unobstructed, you may get hit (and very often will, if you face snipers or infiltrators).

So, what's the point of those icons? To indicate a special case of movement or stance so you can make informed descissions about whether you want them or not.

1) low/half cover:
Your operative will duck behind it, reducing his profile which may reduce the damage taken because some projectiles may hit the cover instead of them or just zing over their head.
A quite interesting thing is that if you have a shield in one of your quick slots and keep it on your back, you'll be quite safe from that side since bullets actually hit the shield first and having a lower profile helps. When in doubt, use cover but don't expect to be invulnerable. You'll lose a head now and then which can be annoying but shouldn't be a death sentence.

2) full cover at corners:
Your operatives (and enemies) will lean out to shoot, giving them a slightly different angle/trajectory path.
This leaning out triggers overwatch/reaction shots.
It also means that if your enemy has return fire (indicated on its icon above your abilities, there's a little white arrow swinging around if he will shoot back), he will have no problem whatsoever hitting you since you just stepped out and present your full profile to him.

3) full cover 'not at corners':
Yeah, that's a headscratcher, who knows why they thought that was a good idea... My best guess why this is indicated at all is because it *might* become a corner tile since the adjacent wall tiles are (in principle) destructible. Or maybe there's just a slightly different stance while leaning against it *shrug*.

...are weird in some respects and some of these things took me forever to realise.
...got even weirder, I'd expect a patch to fix some of this stuff

Good news first: Vehicles' inventories are accessible from the outside, you don't need to stand in a specific position, any adjacent tile seems to work (unless there's some weird stuff with the vehicles' rotation I didn't encounter so far).
However, the vehicles' inventory appears to be limited to only 9 slots from this menu.

If you're sitting inside a vehicle and access the inventory from there, old rules apply including magical scrollbars (see towards the end of this section for pre-Azathoth mechanics):


And if you have more than 9 items inside the vehicle, and take one out from the outside, the rest of the items don't fill the space and you cannot put the item back.

I took the food crate out, the vehicle had some 12 items in it, the spot is still blank but the only option left to me would've been to throw the crate onto the ground.

Some observations (I only have a scarab for now, things might be different for others):

• a scarab on its own can interact with, and loot, resource crates and shift things around to adjacent operatives for 1AP just like an operative; WP gain doesn't get triggered, the crate stays lit (and usable for WPs for an operative)
  
• it cannot interact with its driver
  
• the driver cannot interact with the resource crate (maybe with the Aspida, needs to be checked)
  
• the vehicles interactions are limited to the new inventory (9 spaces w/o upgrade)
  
• you can bring items into a mission, I've tried with a health kit, a grenade and the promo axe and the vehicle had those in its inventory at mission start, operatives could take and use them
  double click the vehicle in the mission start or personnel screen just like an operative to get access to its inventory; you can select the other filter tabs to access all your items
  
• preparing a vehicle this way saves it as 'default equipment' just like with operatives, make sure to check its inventory before you start a mission (say you bring grenade launcher ammo or turrets into a defence with it, then do a scavanging mission, you'd need to clear out its inventory beforehand)

Vehicles can get overencumbered now reducing its movement (if you use the 'old', unlimited inventory):
Moving items into the inventories of its crew reduces its encumbrance and restores its movement again - both Jacob and Sophia are sitting inside the scarab here.

I've read posts/reports that people do not get their items back from the vehicle after a mission, they seem to be stuck inside and there's no obvious way to access their inventories outside of a mission.
I've tried quite hard to replicate any inventory glitches with a scarab but couldn't do it. Bringing Items into a mission and getting everything back afterwards worked without any problems whatsoever - I can only guess that these reports came from people continuing an ongoing campaign and got screwed over by the update.

Everything below this line (in this section) is from before Kaos Engines, some stuff still works, but it'll take a bit 'till this is fully up-to-date

---

Accessing the vehicle's inventory: you need to move one of your operatives into the vehicle, then select him again and open his inventory. Sitting inside the car, he can now access both his own and the vehicle's inventories.

1) Inventory size:
Unlimited, it seems. Initially, you'll see 2 rows of 7 spaces. Fill them all up, and a scrollbar magically appears, revealing a 3rd row. Then a 4th, and so on.
This makes them excellent for scavanging missions since you can take every last bit of the loot and stuff it in your car.
This took me more than 120 hrs to realise.

---

2) Aspidas (Synedrian support vehicle) can transfer items through the door, so to speak. Let me explain:
If you have one operative inside the Aspida, and one outside, standing on the enter/exit spot, the operative inside the vehicle can access his own, the Aspida's, and the other operative's inventories, transfering items from the outside right into the vehicle's inventory. You don't need to step in/step out anymore to store stuff inside them. I have no idea whether that works for the other vehicles as well tho - I couldn't replicate it, so probably not.

I didn't know this for FRICKIN' 280 HOURS!! Three full campaigns!
Shoutout to "Aging Gamers" who just found this out in Episode 80 of his Legendary Festering Skies playthrough at about 6:22

https://youtu.be/-DJQ1Wprio8?t=382

3) You can shoot their guns/rockets even after they have moved the full distance with the remote control ability of a technician. The Scarab can only shoot once per turn, the Armadillo as long as you have AP/WP on your technician (no idea about the Aspida).

4) Vehicles can be navigated so that your exit spot ends right next to a loot box or enemy so you can hop out and for example hit an arthron over its head with a hammer or something. For this you may need to move in single squares to line up correctly, which you can only do with right-click-movement. If you try to left-click one square off-center of the vehicle you'll only get the [info] button, not the [move] button you'd need. sigh...

5) Pathing can be a problem in nest, lair or ancient defence missions making vehicles quite useless. If you have an operative with the Juggernaut Torso, you can destroy more ground tile types than the vehicle itself. Enter Demolition State with your operative and just walk over the tiles that impede your vehicles' movement until you have a path it can take.

Disrupting:
Aside from shooting down flyers, a good source of disruption points is to retake infested havens. Therefore, try to pay attention to the flyer-mission pop-up in the upper middle of the screen ("the Behemoth just initiated a supply flight" or similar) and do not intercept infestation flights. Leave them be, their destruction may give you a few resources and diplo points, but it's way better to do the actual mission while the Behemoth is active to disrupt him. With a couple of infested havens in reserve it's a piece of cake to get rid of him the next time.

Killing:
Once you have the 'thing' you need (it's obvious, really), you select your plane with your a-team while it's sitting somewhere at a base. On the far left hand side of its 'status bar' will be a new button which you click to innitiate the mission to kill him. He doesn't need to be surfaced, you don't need to be at any special location, the only condition seems to be that you're not in mid-flight.

1) Aircraft list:
In the bottom middle is your selected aircraft's status bar. Weapon/Module slots (Festering Skies), a picture of the plane with its health bar, then your operatives.
If you click on the plane's picture, a list pops out where you can quickly(?) select the aircraft you want (it's somewhat better than tabbing at least).

2) Base list:
On the bottom right is a little 'hut' icon which pops out a list of your bases, most notably your 'freed' ancient sites will be at the end of this list, so if you want to mine some orichalcum and forgot where that site was, here you'll find it.

3) Message log:
Is on the right side of your time controls, just in case you've missed something about a flyer mission or where the latest elite training was built.

4) Launching archeological probes to find ancient sites:
It's a little button on the left hand side of your aircraft's status bar, select the aircraft closest to the area you want to scan and click the button to select an area. The area where you can place the probe is a pretty large circle centered on the aircraft you have selected.

5) Camera free rotation:
Per default, the game restricts your camera to 90 degrees of rotation, always presenting the battlefield in a diamond-shaped isometric perspective. To get a better idea about what your actual sightlines might look like, you can unlock the free camera in the options:
6) Zoom options in the battlemap:
A couple taps of
[T] to zoom in, very useful for aiming laser mounts at specific body parts,
[G] to zoom out again
Holding middle mouse button zooms out all the way temporarily to get a view of the battlefield. Useful to get the lay of the land and to see perception ranges of enemies not yet in alert.

7) Speaking of perception ranges:
Hovering over the enemy will display a circle of his perception versus your currently selected operative's stealth - the size of this circle is specific to the operative you have selected. Sight lines apply, moving behind obstructions (usually) won't trigger them. If you're very close, they might hear you through obstructions, but that's rarely an issue.
Also handy to figure out whether a Chiron already knows about you (or allies in defences) and will shoot at his turn or just amble around - if the perception ring displays, he's not alerted, otherwise he is and will shoot. No issue with worms, but goo or explosives ready to go might want you to head inside buildings.

Some stuff that may be ambiguously worded or isn't quite apparent.

Heavy
War Cry: displays its graphical effects on hidden enemies so you can see where they are (if your view is on the same z-level, tricky with multi-storey buildings)
- only lights up as available IF there are enemies in range, so you can see whether or not there may be enemies around; e.g. you fly up onto a roof, the skill lights up -> there's something around/below you

Boom Blast: not only for grenades/launchers but also reduces mounted weapons cost to zero, including the Destiny III
- also reduces cost/increases range for worms and goo bombs for Mutoids (Corrupted Horizons DLC)

Rage Burst: cost depends on the weapon used, so you can e.g. burst fire rifles for 2AP/5WP, pistols for 1AP/5WP
- tricky to aim, it's center (3rd shot out of 5) 'snaps' to the body part you're hovering over (just like the Destiny III)
- best used against large enemies at close range, almost useless against groups of tritons/arthrons for example

---

Assault
Ready For Action: can also access other operatives' inventories to swap things into their ready slots or to reload a weapon for free (take weapon + ammo, put weapon into ready slot, hit reload, give weapon back, all for free)

Rapid Clearance: can trigger multiple times with one action if you happen to kill more than one enemy
- killing a friendly will also give AP

---

Sniper
Marked For Death: is a status effect on the enemy, not on the sniper; all operatives will deal 10 points of damage more per bullet/laser/melee. E.g. a deceptor hitting all 12 rounds would deal additional 120 points of damage

---

Technician
Remote Control: works on 'fresh' spider drones, giving them both AP to move and ability to explode on their first turn
- can shoot turrets', Aspidas' and Armadillos' weapons until you run out of AP/WP, even after full movement. The Scarab's rockets can only be shot once per turn, but you can move fully beforehand if you plan to use RC

---

Berserker
Armor Break: description is wrong, you will apply 30 shred damage with your next attack which replaces whatever value your weapon has

Bloodlust: I feel it's worded poorly, I hope this makes more sense:
X% (30%) health lost would increase your speed and damage by (X/2)% (15%) of their base values (additive, not multiplicative increases)
Example: Mattock base damage 220, CQS 20% bonus, 20% missing health:
220+(220*0.2)+(220*0.1) = 220+44+22 = 286 damage

Ignore Pain: disabled body parts remain functional, but will bleed which needs to be healed

Adrenaline Rush: you can use the recover ability for 1AP to regain WP (towards the end of your turn)
- the daze effect in the next turn can be negated by getting the armored head mutation

If you've never faced problems overwatching, skip this

I still see people on streams or in videos who go totally berserk because their overwatch didn't trigger and take the easy route to blame the game as buggy instead of thinking about what went wrong, so here goes:

Your overwatch extends as a cone with a circular base from your gun towards the object/floor you've clicked on. The center point of the circle will be at the exact pixel you selected and the cone will be cut off perpendicular to its center line.

Common errors:

1) Aiming upwards, may happen because you've scrolled all the way out to get a better view, but that also shows the upper floors and roofs of buildings and may throw off your positioning:

---

2) Aiming at a wall to overwatch a door; since the cone cuts off at the wall, the enemy is perfectly safe if he just steps to the side to take a shot, so make sure to aim inside the building, clicking on a floor tile:

---

3) Aiming from above at a lower level; since the cone's base is perpendicular to your line of fire, this may happen:

---

4) Objects get in the way, against small critters like worms or myrmidons even a table or some pots may cast a 'shadow' behind them that covers their profile:

---

5) One enemy just has badly defined 'trigger points' (or whatever you want to call them) and it is actually the game's fault...
The Acheron (Corrupted Horizons DLC) simply doesn't trigger overwatch with his ballon-like husk, nor does he appear as 'I have vision to it' if only its husk is visible to you. You can still shoot it in free aim, the game's just silly in regards to them. Oh well.

Yeah, 'twas long, but I hope it helped a little bit.
Peace.