Upon repeated playthroughs of this game, I've uncovered a variety of mechanics and optimizations I felt would've saved me from much frustration early on in my playthroughs. I've compiled these little tidbits of information to hopefully help both brand new and experienced players alike with rather obscure yet helpful tips I've picked up over my time playing this. These tips range from understanding the UI, optimizing gameplay, and utilizing odd quirks involving the game's engine and AI. This guide is also (mostly) spoiler-free for those wanting a genuine story experience. Hopefully it will help players learn what they normally would pick up only through countless mistakes and frustration otherwise.

• Taking off and landing takes about 12 hours in the geoscape. Keep this in mind while scanning, as it's usually better to finish scanning an area before moving on to scan somewhere else, even if the new scanning location has a quicker scan time.
  
  
• When scanning for rumors, the most valuable things to scan for at the start of the game are scientists, engineers, avenger power, and resistance contacts. In late-game, it obviously depends on what you need the most, although extra avenger power and resistance contacts is always valuable until you max out either.
  
  
• You can use the scroll wheel to zoom in on the Avenger, and use edge scrolling to move the camera.
  
  
• Ignoring any mission (save for when you are given no choice but to ignore two of three missions while countering Advent activity) results in you losing contact with the resistance within an area. Failing the missions has the same result (including abandoning them).
  
  
• You get more soldier customization options once they get a nickname (besides just editing their nickname, of course). You get even more options (including new helmets) when you get new armor.
  
  
• A soldier's personality (intense, happy-go-lucky, and so on) changes their voice lines, too.
  
  
• When making a character pool and setting it to "use character pool only" for the game's random soldiers, this option doesn't work unless you have 25 or more characters in the character pool. Otherwise, the characters in the pool will be mixed with randomly generated soldiers.
  
  
• Images taken via the photobooth appear in the overworld. They only appear plastered on walls, so the extra filters (like L.C.D.) don't do anything besides change their appearance.
  
  
• The photobooth pictures are stored in the Xcom 2: War of the Chosen folder in your My Games folder. If you've done multiple playthroughs or take a lot of pictures, it can take over a gig in memory.

AVATAR PROJECT

• Even though the game doesn't tell you about it until it has three bars, the Avatar progress still proceeds at the start of the game. You're still on a timer in the beginning.
  
  
• You don't instantly lose when the Avatar project's bar fills up. You'll instead get a timer telling you how much time you have left.
  
  
• Reduce Avatar progress as soon as possible, rather than saving it for when you "need it." The Avatar progress proceeds on a timer which resets when it goes down. Doing it right before this happens (which isn't possible to know until after it proceeds) resets the timer, giving you more time than simply waiting for it to go up and then making it go down.
  
  
• Completing story objectives lowers the Avatar project's bar. These (non-spoilered) objects are: using the Skulljack for the first time (and killing what spawns), using the Skulljack on the second assigned target (and killing what spawns), and completing any combat mission which is deemed as a story objective. For a majority of these objectives, you need the shadow chamber.

SOLDIERS

• When the game begins, you get more rookies than you feasibly need. This serves as a buffer for if your soldiers die. In general, you should rotate about 18 or so soldiers, perhaps even less once you build the advanced warfare center, both to deal with recovery times and as a backup for soldier deaths. You don't need to train up everybody.
  
  
• Soldiers get XP for completing missions, but there's other quirks. If a unit is on a mission where a teammate gets a kill, they get partial XP (with Rookies and Rangers getting a small bonus, and Specialists and Psi-Operatives getting a slightly larger bonus).
  
  
• Even if their XP is past the threshold for a promotion, soldiers will only level up once they get a kill that pushes them too or beyond the XP requirement.
  
  
• Most XP comes from completing missions. Getting kills helps, but it's more time efficient (as in your own real-world time) to just do missions rather than farming reinforcements, even if you still gain a fair bit of XP for doing so.
  
  
• You don't "waste XP" if soldiers continue to get kills after they earn a promotion on-mission. However, if a soldier somehow earns enough XP to get two promotions on a single mission, they'll need to go on a second mission and get a single kill to earn the other promotion.
  
  
• Soldiers level up slower depending on the difficulty. This doesn't make too much of a difference since each difficulty increases the number of aliens on-mission, though. On Commander difficulty, your soldiers will level up at an extremely quick pace due to this quirk, but Legend sees soldiers promoting at the absolute slowest for higher ranks.
  
  
• It's okay to lose soldiers. It's alright to get an entire squad wiped out. It's perfectly fine to lose each and every one of your top captains from a botched mission. Although the game's overall difficulty will not change, the game is made in a way that it eases up or gets harder based on your failure or success. If you fail a mission, odds are you won't fail again for a while--it might even help you in the long run. The game will know if you need a resource, even if you fail a mission meant to give you it. No matter how skilled a soldier is, the cold fact of the matter is that they're ultimately replaceable.
  
  
• When a soldier is "tired," it just means that they're more prone to panicking. This can happen if they're shot, a teammate is shot, a teammate is mind controlled, or somebody dies. They also might get some form of PTSD when returning from the mission, but this can be cured via the infirmary. Once a tired soldier returns from a mission, they won't be able to go on another mission for a while. Basically, the function of "tired" soldiers is just to save you from yourself: it's the game's way of encouraging you to not rely on only the same handful of soldiers in case you lose some of them.
  
  
• Use the Tactics School to train Rookies rather than sending them on missions. It's better to use the slots they would normally take on-mission to rank up better soldiers while you train the Rookie, since you're essentially leveling two soldiers at once by doing so.
  
  
• Rookies can level up on covert missions. It's worth it to send them out on those or train them in the tactics school rather than sending them on normal missions. That way you can train up other soldiers without rookies taking a slot on-mission.
  
  
• Every stat on a soldier improves with their rank, obviously. Hence why rookies tend to have the absolute worst aim.
  
  
• A class becomes more or less useful compared to other classes depending on their level. Grenadiers are useful early on, but drop off. Sharpshooters are useless early on, but are incredibly powerful at high levels. Rangers are powerful but rely on team support, and rely on said support less so as they level up. Specialists excel at team support but are generally decent on their own, but improve at team support as they level up. Despite this, every class is essential for team success.
  
  
• You lose any items a soldier was carrying if they are left behind somehow (living or dead) in any mission which ends in an extraction. This includes unique weapons or armor, which are gone for good.

BASE AND RESEARCH OPTIMIZATION

• Shielded power cores make it so any facility built on them do not cost electricity. It also boosts the electricity produced by generators. However, the best facilities to put on them are the psi labs and shadow chamber rather than generators, since each require more electricity than a generator placed in the same spot can produce (but only if you want the psi lab to train two soldiers at once, which is a little bit overkill; if you think one psi soldier is enough, then you're better off putting a shadow chamber and a generator on the cores).
  
  
• The available facilities are (in WoTC): tactics school, training center, laboratory, advanced warfare center, turret control, resistance comms, power cenerator, shadow chamber, psi lab, workshop, proving ground, and resistance ring. There's no benefit based on the placement of these facilities besides where workshops are placed (since they act as free engineers) and what facilities are on power cores (explained above).
  
  
• The facilities which use engineers are: turret control, advanced warfare center, resistance comms (takes up to two), power generator (ditto), workshop (ditto), resistance ring, psi lab, and proving ground. Thus, in total, you will need nine engineers to run every facility at maximum capacity, ignoring the workshop which gives you free engineers.
  
  
• You can build one of every facility in the Avenger if you have no duplicates. However, the psi lab becomes obsolete when you have two maxed out psi soldiers (unless they die somehow, which shouldn't be likely), the workshop is useless once you have enough engineers, and the laboratory has no point once you research everything. You need two resistance com stations to contact every country, though, and two power generators possibly.
  
  
• The most important resource is obviously supplies. Thus, your early-game should be focused on the long-term goals of gaining as many supplies as possible through contacted regions and radio relays.
  
  
• The game is player-phase focused, meaning it highly favors offense over defense. Due to this, rush magnetic weapons, only putting "Resistance Radio" before it. You unlock magnetic weapons research by studying modular weapons. Afterwards, try to rush plated armor when you can. From this, you can try your best to rush "Elerium" to get plasma weapons and powered armor afterwards, but you need various alien autopsies to unlock this.
  
  
• You can't use weapon mods or PCS's until you study modular weapons and alien biotech respectively.
  
  
• You can't autopsy other aliens until you autopsy an Advent Officer.

ARMOR AND WEAPONS

• Spider/Wraith armor gives bonus dodge and movement. EXO/WAR armor gives bonus armor. The Alien Ruler armors give varying bonuses.
  
  
• Weapons are more or less accurate depending on the range. Assault rifles and shotguns work better the closer you are to an enemy (with assault rifles having less drop off than shotguns). Miniguns are most accurate around five tiles away and get less accurate as you get closer or farther. Sniper rifles are most accurate a large distance from an enemy, but will get less accurate the farther away you get after this bonus.
  
  
• The "stock" (assured damage even on miss) weapon mod's higher tier variants don't do an assured 2 or 3 damage if the enemy has armor. They will still always do at least 1 damage, however.
  
  
• The repeater weapon mod (which can instakill enemies) also instakills things like late-game enemies with massive health pools, the Chosen, Alien Rulers, and so on. There's nothing it can't instantly kill, so an entire squad using these will invariably ruin an enemy that's focus fired.
  
  
• Despite the laser sight being most effective on shotguns, it still applies to other weapons according to their effective range. For example, a sniper rifle with a laser sight still receives the max critical hit bonus on an enemy at long range as long as the enemy is at the start of the sniper rifle's effective range.
  
  
• If you hover over the gun icon on the lower right of the screen when you select a soldier, it tells you what weapon mods and special ammo the gun has.
  
  
• A certain sniper rifle, Darklance, only takes a single action to fire, letting you reload or move and fire on the same turn. The pistol which pairs with it, Darkclaw, ignores armor. Lastly, a special katana you get as a reward cannot miss and ignores 5 points of armor. It also does a full tier higher damage from other melee weapons, but cannot apply any status effects.
  
  
• If you have the Tactical Legacy Pack, doing the missions which come with it (regardless of rank) gives you unlocks in the game. These are all mostly cosmetic, but the weapons you get have weapon mods pre-attached, and the sword you get also has a bonus hit chance. The missions, although containing spoilers for some enemy types later on, serve pretty good as a taste of late-game missions during a normal playthough. It can be seen as a "scenario" tutorial for the main game.

ITEMS

• Chrysallid poison can only be cured by medkits, and won't ever go away otherwise. If your soldier gets poisoned by this without a medkit, you should call an EVAC and get them out before they die.
  
  
• Merely carrying a medkit makes the owner immune to poison (including from Chrysallids), even if they run into a poison cloud.
  
  
• Healing a soldier doesn't reduce their wound recovery time.
  
  
• Status (or "damaging") grenades shred armor like normal grenades do. The only grenades that don't are support grenades (frost, smoke, and flash). EMPs ignore armor, but does not shred it.
  
  
• The size of any grenade's explosion (included support grenades) increases when fired by a grenadier.
  
  
• Flashbangs can remove overwatch.
  
  
• Flashbangs do not affect teammates (unless they're mind controlled). However, smoke grenades can benefit enemies.
  
  
• Using a flashbang on a Sectoid will release any mind control or psi zombies they have. It will not, however, calm a soldier they have panicked (although killing the Sectoid will do all three).
  
  
• Proximity Mines break concealment, but placing them do not. The purpose of them is to basically give you two free turns. First you place the mines, set all your soldiers to overwatch, then let the enemy trigger the mine on their own turn. Since enemies don't get to act if your squad is revealed on their turn (unless it's through accidentally flanking one of your soldiers), all they'll get to do is reposition.
  
  
• Damaging grenade types: fire (damage over time, prevents abilities, can be cured by hunker down), gas (damage over time, aim penalties, cannot be cured), acid (damage over time, affects nearly all enemies and cannot be cured), EMP (high damage to only robotic enemies and lowers hack defense).
  
  
• The Ultrasonic Lure does not work in missions without Lost, obviously.
  
  
• Bluescreen rounds/EMPs work on Sectopods, Codexes, Specters Spectres, Turrets, phase 2 Andromedons, and MECs.
  
  
• Dragon rounds do not affect robotic enemies and the Gatekeeper. Andromedons are affected by dragon rounds regardless of their state, however. Setting an enemy on fire limits a few of their abilities.
  
  
• Acid rounds do not affect chrysallids and Andromedons in any state. However, "acid burn" does not incur any status effect beyond the same damage over time as being on fire.
  
  
• Armor piercing rounds do not actually completely nullify armor, they just ignore a specific amount of armor. It is possible for an enemy, namely Gatekeepers, to have more armor than what APRs can penetrate.
  
  
• Mimic Beacons are extremely effective as decoys, since enemies will disproportionately prioritize them over any other unit. As a matter of fact, enemies will only ever ignore a decoy if they cannot see it or if they are a melee unit and right next to a normal soldier. Carrying one is a good countermeasure for any mistake, and carrying two makes it nearly impossible to lose a soldier (save to things like the Chosen, who don't fall for the decoy).
  
  
• The improved Skulljack improves hacking, adding a +20 bonus, even when you're just hacking a normal terminal and so on. Thus the best class for Skulljacks are Specialists.
  
  
• The Skulljack is an instant kill, but has a fixed 70% hit rate and can only be used on Advent/Codexes. It also lets a soldier move after using it, but only if they had another action.
  
  
• If a soldier dies or is knocked unconscious, you won't get their gear back if the mission ends in an EVAC and you don't have somebody carry them. If a mission does not end in an EVAC, you'll keep anything that can be gathered in the area, including loot pickups and enemy corpses.

• The first retaliation mission is meant to introduce you to one of the Chosen, assuming you didn't set the game to use the introductory mission for the War Of The Chosen DLC. While you can certainly kill the small handful of aliens attacking the outpost, you're mostly intended to "lose" against the Chosen insofar as they will usually just extract knowledge from your soldiers rather than kill or capture them. It's smart to send in a handful of rookies you don't mind losing to this mission.
  
  
• In the "eliminate the Advent official" missions, the mission only fails when the official reaches the escape area, not just when the escape area appears.
  
  
• In the missions where you need to mark supply crates, Advent does not begin marking the crates until you break concealment. You get every crate left if you kill every enemy, and crates stop getting marked if only Lost remain.
  
  
• There are no missions where there are "infinite" reinforcements, save for a certain mission where you get to control more soldiers than normal (you'll know the one). Even missions with Lost have a finite number of Lost reinforcements, except for one mission type where you need to rescue a VIP standing next to an automated turret.
  
  
• You don't lose anything for abandoning the assault of an Avatar facility other than having to fight the same enemies again, but only if you unlocked the facility via a facility lead. If you unlocked it through contacting the region it's in, you'll lose that region. If you somehow unlocked the facility through a facility lead and then contacted the region afterwards, you'll still keep the region if you abandon, though.
  
  
• When you fight a Chosen, the mission timer freezes. This only works when you actually witness the Chosen, though. Merely having the Chosen spawn does nothing.
  
  
• When being ambushed in covert missions, despite what Central says, you can take it slow and pick off enemies you find while trying to escape. Ambushes usually have a single "reinforcement" at the beginning (where two enemies drop in front of you) and two to three patrolling enemies in the area, with Lost scattered around.

• Dashing rounds mobility up. In other words, using two actions to dash lets your soldiers move slightly farther than using an action to move and then doing it again.
  
  
• Never dash unless you're catching up to your unit or retreating. If you dash into enemy lines, you'll invariably activate the next batch of enemies.
  
  
• Enemies standing on building rooftops or raised platforms will take fall damage (around two points regardless of distance) if the footing under them is destroyed. This can be done with explosives, but missed shots can potentially do this as well.
  
  
• If an enemy (or soldier) is near or taking cover by an objective or explosive object, any shot which misses could potentially destroy or detonate it.
  
  
• Cars and other explosives actually have their own healthbars (which are hidden). Cars typically explode after a turn, but will explode instantly if they're hit again while on fire. The explosion radius is a two tile radius around the car, generally. This varies for other explosives.
  
  
• Any explosive object which is primed to explode (signaled by sparks and fire) does so on the start of whatever side's turn set them off. For instance, if the aliens prime an explosive object on their own turn, then it will explode the next time it is the alien turn.
  
  
• Although trucks can explode, only the front of the truck actually detonates. The trailer will not (although it can be destroyed by the explosion).
  
  
• Large trees seem to be the only objects which require two explosions to completely destroy.
  
  
• Using a grapple doesn't cost an action, but it does activate overwatch on enemy units.

• You lose concealment if you complete the map objective. Soldiers with the "Conceal" ability can go right back into hiding and EVAC out, though. You can do solo stealth missions with a single soldier who knows "Conceal," although there's no particularly good reason to do so.
  
  
• Enemies cannot see a concealed soldier if they're behind cover. If the soldier moves, they will be spotted regardless.
  
  
• Hacking advent towers or enemies doesn't break concealment unless you fail it. If you hack to control a robot, however, they will break concealment if they're near other enemies.
  
  
• Dashing through doors instead of stopping in front of them to open them breaks concealment, as does jumping through windows. It also creates noise which lures enemies.
  
  
• Overwatch does not have an aim penalty when shooting while breaking concealment. The game calls this an "ambush."
  
  
• SPARKs, despite not being able to take cover, can still hide behind cover in stealth just like any other unit.

MECHANICS

• Using the Tactical Legacy DLC, you can change the soundtrack to a 1994 XCOM inspired theme. Just do it. Trust me.
  
  
• Hunker Down on low cover (30 + 20 = 50) is better than standing normally in high cover (40). Hunker Down on high cover (30 + 40 = 70) offers the best defensive bonus, obviously.
  
  
• You cannot be critically hit while using Hunker Down, even if you are flanked.
  
  
• The closer you are to flanking, the better your hit percent will be. The game calls this a "good angle bonus."
  
  
• Enemies patrol randomly unless they're activated. They're attracted by sounds of combat (explosions and missed shots especially) and civilians who run when your soldiers approach them, but they head towards the sound and not your soldiers specifically. However, completing a map objective makes soldiers head directly towards you. You can use this to set up overwatch ambushes.
  
  
• Enemies often move when flanked. If they're in high cover but flanked by one of your units, it's smart to set other units you intend to shoot them with to overwatch for an easier shot.
  
  
• While overwatch has a 15% aim penalty, this is completely negated as the enemy is out of cover when overwatch activates. Since low cover gives a 20% defense bonus, an overwatch shot on an enemy leaving low cover effectively has a 5% better chance to hit than firing on the enemy while it's still in low cover.
  
  
• Reinforcements do not get to attack on the first turn, they only get to reposition. Most MECs will be set to overwatch rather than try to reposition, though.
  
  
• Your soldiers can still use the EVAC even when they have no actions. Thus, you can dash to an EVAC in emergencies.
  
  
• Picking up a body does not cost an action, but putting one down does.
  
  
• XCOM gets ability points at random for doing certain actions. These are: shooting from a height advantage, flanking, getting a kill from concealment, and getting a "combo kill" (the means of which varies). Individual soldiers get their own personal ability points from just leveling up, the points given depend on "combat intelligence."

ENGINE QUIRKS

• The game's luck is based off of a seed. The only way to change a result is to do something different, reloading the same action does nothing, you save scummer.
  
  
• You can tell when a shot misses before the tooltip by watching the barrel of your soldier's guns. If they suddenly move away from where the soldier was aiming, you know the shot had missed. This isn't helpful since you've already told them to take the shot at that point, but it lets you know earlier than usual.
  
  
• When a soldier moves and you can't swap to a different soldier as they're moving, this means that your moving soldier has discovered an enemy during their move (or they scared a civilian). This isn't particularly helpful, but you'll know earlier than usual.
  
  
• Besides shooting, or perhaps even more so, you'll be reloading and using overwatch frequently. Therefore, learning the hotkeys for reloading, overwatch, and swapping soldiers can greatly speed up gameplay, as you can quickly go through each soldier and tell them to all reload or overwatch at the end of their turns.

• The T and G buttons zoom in and out. Q and E rotate the camera.
  
  
• The game is like Crysis where its graphics were partially designed with the idea that it can only be run on max settings with a theoretical computer in the future, so don't expect to run at max even with a high-end computer.
  
  
• In the upper left corner, the game tells you when reinforcements are arriving. "INCOMING" means the reinforcements will appear at the start of the next turn.
  
  
• If a soldier is flanked, a yellow shield icon will appear by their health bar.
  
  
• Any enemy on overwatch has an eyeball next to their healthbar.
  
  
• When moving (in War of the Chosen), you'll get a "target preview" telling you what will be visible in that spot. Gray highlights means a visible enemy will no longer be visible, red means a target will be visible, and yellow means a target will be flanked.
  
  
• In both War of the Chosen and vanilla, you can tell which enemies will be targetable by hovering over where you want to move and looking at the enemy's healthbar. If a target appears by their healthbar, this means that enemy will be targetable upon moving there.
  
  
• When you are confirming an action in combat, there is a symbol which tells you specifically if the action will end your turn/takes two actions instead of just one. If there is an icon that resembles ">|" to the right of the action confirm button, that action ends your turn. If it is absent, then the action will only take one action point (although it will end your turn if you have only one point left).
  
  
• On the lower left of the screen, if your soldier has a buff/debuff, hovering over the green/red upwards/downwards facing arrows tells you what buffs/debuffs the soldier has.
  
  
• When selecting a target to shoot, hovering on the icon for your target tells you what buff/debuffs the target has and what is affecting your hit percentage.

• You can see the Chosen's weaknesses again by clicking on their icon which appears in the upper right corner.
  
  
• The Lost are weak to fire. However, fire bombs still attract them.
  
  
• Not only does any grenade explosion lure Lost, but environmental explosions and using any powered/heavy weapon besides the flamethrower will also lure them.
  
  
• Killing a Lost with melee or explosives doesn't give your actions back, only shooting it with a gun (including pistols). However, using abilities which end your turn (like fan fire or rapid fire) doesn't give your actions back.
  
  
• Since the Lost typically come from areas you haven't explored or can't see, you can use explosives freely when fighting Advent since the Lost invariably spawn near them instead of you. Advent usually aim for Lost over you, but since their aim is worse, they'll lose a turn fighting them off via missing usually.
  
  
• The Assassin is the hardest Chosen to fight by far. The Hunter is the easiest early-game, but the Warlock becomes the easiest once you have more beefed up soldiers (who can more easily chase him and resist his attempts at mind control) while the Hunter stays a consistent threat.
  
  
• When a Chosen blinds a soldier, you can still swap to other soldiers to get a better view of the area before moving the blinded soldier. They can still shoot, but they need to be closer to an enemy to fire.
  
  
• When you fight a Chosen, the mission timer freezes. This only works when you actually witness the Chosen, though. Merely having the Chosen spawn does nothing.
  
  
• Chosen are not affected by psychological impairments like panic, disoriented (including from flashbangs), and mind control. They also do not fall for mimic beacons.
  
  
• Sectoids are weak to any melee attack, including Templars or the Lost.
  
  
• Using a flashbang on a Sectoid will release any mind control or psi zombies they have. If a Sectoid panics a soldier, only killing the Sectoid will release them early.
  
  
• Since turrets can't move and are bolted to the floor they're on, breaking the floor underneath them when they're on a destructable surface will instantly kill them.
  
  
• Codexes do not multiply if attacked while disoriented.
  
  
• Chrysallid poison can only be cured by medkits, and won't ever go away otherwise. If your soldier gets poisoned by this without a medkit, you should call an EVAC and get them out before they die.
  
  
• You don't lose or gain anything by killing civilians found in Advent-controlled cities. You should still feel bad, though.
  
  
• When a Spectre shadowbinds a soldier, that soldier isn't permanently unconscious. They are revived by the Spectre dying (which also kills the clone) or killing the clone itself.
  
  
• Mutons can counter melee attacks, and they do so frequently enough that it makes it too risky to go for. They're the only units which do this, as Berserkers do not.
  
  
• Andromedons lose any cover bonus when they enter their second phase.
  
  
• Despite the game hyping up Sectopods, Gatekeepers are significantly more threatening. They have a huge innate defense bonus, a ton of armor, have an AoE attack which does massive damage, have huge psi defense, is much more mobile, and can also attack twice in one turn. There's also no unique methods (like bluescreen rounds) which help you specifically take them out.
  
  
• Every alien from Xcom 1 has a counterpart in 2. Outsiders are Codexes, Ethereals are Avatars, Floaters are Archons, Mechtoids are Andromedons (functionally), Cyberdiscs are Gatekeepers, and so on. Seekers are the only enemy from 1 that don't have a similar unit in 2. Maybe Specters, but Specters are more like male Codex than anything.
  
  
• When fighting Alien Rulers, these alien types are frozen longer by frost grenades than normal aliens. But this is only true in War of The Chosen.
  
  
• Alien Rulers don't get a "reaction" turn against a soldier they can't see, nor do they get a reaction for reloading or abilities that don't cost an action (but only in War of the Chosen).

SKILLS

• SPARKs with the "Bulwark" skill (which gives high cover to allies if they stand near them) also gives high cover to enemy. If an enemy is right next to a SPARK and the SPARK aims at them, the enemy will still have a high cover bonus.
  
  
• When a Templar uses their "Parry" skill, enemy units will target them first, even if it isn't tactically advantageous. It's a deceptively powerful ability.
  
  
• Despite appearing to be a sniper rifle, a Reaper's gun and abilities are more akin to assault rifles (including being more effective at close range).
  
  
• Obviously, given the nature of Skirmishers, their guns should carry expanded magazines/autoloaders, repeaters, and hair triggers to compliment their ability to fire multiple times.
  
  
• While Specialists can hack objects from a distance, they can also access objectives which require hacking (like disarming the detonators).
  
  
• The void rift psi ability also allows the user to attack with insanity, with the usual effects of insanity.
  
  
• Hacked/mind controlled enemies are only hacked/mind controlled for two turns, with the first turn having said enemy immediately lose all their actions. After the second turn, they'll immediately be able to attack your soldiers, so plan accordingly (or just kill them before they return back to the enemy side).
  
  
• Hitting an enemy on overwatch removes it.
  
  STATUSES
  
  
• Putting an enemy in stasis removes any mind control they have, either on themselves or if they're mind controlling a soldier. The same applies to soldiers.
  
  
• Only in the base game, and when in cover, moving a single tile to adjacent cover does not activate overwatch. Any farther will. War of the Chosen removes this for some reason.
  
  
• Burning units can be put out by hunkering down (but only in War of the Chosen).
  
  
• Poison spreads to nearby units if they're adjacent to a poisoned unit.
  
  
• At higher bond levels, soldiers can cure their bondmates of any negative mental effect by standing next to them, including disorientation and mind control.
  
  
• When a squadmate is dazed, a soldier can revive them even if they have no actions left. Thus, you can have soldiers dash over to dazed teammates or fire before reviving them.