Tactics (Long War)

General Advice & Tips

This covers anecdotal or general concepts and tips that might not fit into any other place, usually just player specific styles or advice that might help you during the tactical combat.

Terror Missions.
It is usually worthwhile to throw battle scanners around and "spy" on enemies. Civilians you can see (in this case from battle scanner) cannot be killed by un-triggered aliens, and you also get to see what pods are on the map.

Chem Grenade
An extremely useful type of grenade, try it over flash-bangs and psi-grenades. Although it doesn't affect the ever annoying chryssalids and thin men, it can be used against all other enemy types. Reduces aim, movement points and damages upon actions. Also extremely useful against later Cyberdisks, mechtoids and sectopods with insane hit-points and damage reduction. Can effectively reduce damage reduction of hardened enemies to 1-3 from (late stage) 8-10, making them much easier to kill.

Exalt Missions: Tips & Tactics.
1) It is usually easier to guard the transmitter rather than the encoder. If Exalt spawn near the encoder and rush it from the beginning, don't risk your troops to rush it too. Just converge at the transmitter for a last stand.
2) Blow up all cover at encoder or transmitter. Exalt are dumb enough to rush into that area and stay in the open.
3) Consider using engineers as operatives for extra grenade spamming. As the operative cannot carry a main weapon, it is one of the few classes not hindered by this mechanic, as their main damage source (grenades) can still be equipped. Assaults may also be useful for dashing hacks (use Run N Gun).
4) You can hack relays to disable exalt weapons until they reload. Try and keep your operative in range to hack one in case you get overrun. Note however that this may backfire, as Exalt may end up using rockets and grenades in their turn.
5) On Exalt missions where you need to hack 2 relays, Exalt reinforcements spawn when the operative is in position to hack a relay (a.k.a when he moves right next to it), and not when he actually hacks it. You may find it easier by not hacking the relay on that turn and wait for the reinforcements to spawn. As they will usually enter overwatch, you can proceed to hack the relay on the next turn, effectively disabling overwatch fire, ass well as their weapons until reload. They are much easier to deal with this way.

Chatter on the Wind
Every two turns your soldiers will "hear" the enemy movement beyond your line of sight. The directional indicator you are shown points to the CLOSEST enemies to your soldiers. The only aliens that make no audible sound during this reveal are outsiders, though they will still trigger the indicator's mechanics (as usually they'll be the last aliens in a UFO assault mission). And learn the sounds the various enemies make during Alien Activity to get a feel of enemy composition: Sectoids chitter, Thin Men rasp, Mutons roar (Berserkers & Elites have slightly different sounds), Floaters rocket and growl, Cyberdiscs make.... ufo-y sounds, drones hover-whine, Mechtoids and Sectopods share heavy footfalls, you hear the Chryssalids in your nightmares, and the Etherials 'talk.' The length of Alien Activity will also give you an idea of how many aliens (and EXALT agents) there are left. On Council and Covert Op missions, if it barely lasts a moment, there are no enemies in play, so continue with the mission without worry (until the next airdrop trigger, anyways).

Scatter Control
When aiming a rocket, try to at least double the expected scatter. Your rocket has a 95% chance of landing within a circle of that distance, although it's more likely to hit closer to the center.

Medics: They aren't useless
A medic is one of the most useful classes to have around, they can keep your soldiers healthy during battle and they increase the survivability of friendly (and enemy) soldiers with their smoke grenades. They may lack the killing power of the other classes, but when you get poisoned by a thin-man or strangled by a Seeker, you'll be glad that you have them with you.

Shreddin' Assaults
Assaults have a small item that confers "shredded" to any enemies hit. This applies not just to shots from guns, but also damaging Psi attacks. Note: Beta 14f has removed shredding effect from damaging psi attacks. Verify?

Divide and Conquer.
Usually it is never a good idea to split your team into two, but on urban maps, there is some merit in doing this. When you have both your Squad upgrades, you can split your squad into fire teams of four people. This is useful because it lets you breach buildings and other structures much more efficiently and sets you up for more flanking maneuvers. It also lets you get out of deadlock situations where you are in a prolonged fire fight with Alien opposition, without any opportunity to move forward.

S.H.I.V all the things.
Liberally use S.H.I.Vs, they are much better than the standard rookie, can take more damage and can create moving cover. They might not get any experience and be less effective than a regular soldier, but they can be outfitted to oblivion due to the much expanded S.H.I.V tree, present in Long War. A S.H.I.V does not suffer from fatigue either. If you want to try and take all the missions that the game throws at you, having a large contingent of S.H.I.Vs is almost a requirement.

Battle Scanners.
Battle scanners become a requirement when seekers start coming into the enemy squad rotation as they can seriously wreck any well laid plan. Seekers have had many shackles taken off their AI, so 4 seekers can decloak and strangle you in one turn unless you do something about it.

Grenades first.
You might have a juicy HE grenade Target hiding behind a wall. You have the perfect throw, but think before you throw. You might remove his cover, but you might also add line of sight to the three other aliens that was on the other side of the wall, now you have to contend with more enemies and you might be caught in a very bad position. As such, generally throw the Grenade as the first thing, not the last.

Meld doesn't matter.
While not true, it is not worth potentially losing valuable soldiers to recover it. If it's in a good place to grab, then by all means. If not don't waste a soldiers well-being on it. Also, the better you are doing, the less Meld you receive, so don't worry about missing it. Meld becomes increasingly necessary in the late game. In addition to meld canisters, meld is gained at an automatic rate of 0.2 alien corpse brought home from a mission (rounded down). Mechtoid and floater/H.floater corpses also provide slightly higher fractional meld.
Rushing the meld canisters can be risky, one strategy is to get in sight of the meld canister and then wait and see what kind of sound it's making. Meld canisters only expire the turn after they are chirping at a frequency of approximately 1/sec (once per second). Listening to the canisters can thus help you gauge how aggressively you need to act. Put the camera to 'terrain gliding' with F9, and look around when starting a mission: you may catch the movement of the canister's 'turret' if you look for a bit. On top of UFOs is a common place (and are easy to spot in this method), so if you do not have a way to access them, consider them a write-off and take your time, unless you think you can rush to complete the mission before it goes off.

Explosive Terror solutions
The most dangerous part of terror mission are the roaming Chryssalids. Chryssalids will frequently charge you in a bunched up group, which makes them excellent targets for grenades and/or rockets. You might not get any carcasses, but that is a small price to pay. This is one of the few occasions where AP grenades really shine. A MEC with a flamethrower is the mother of all chryssalid fears, consider moving MECs near the end of your turn if you know chryssalids are on the map.

Cover, cover, cover!
Always keep your units in high cover, for that 45 defense and damage reduction. If in low cover, hunker. Hunkering in low cover is BETTER than standing in high cover. 45 defense with 1 damage reduction vs 60 defense with 1.33.

A plethora of specimens.
A good, albeit dangerous, way to earn more scientists and money is by giving captured aliens to council nations. As such, you should always try to capture at least one Alien, when doing a mission. Downed Scouts and Fighters are excellent ways to do this. You can have a near infinite number of Captured aliens at your base and countries will usually only ask for one specimen per request.

Knowing is half the battle!
In Long War, you will be given a short description of what type of terrain you will be fighting on. This is very useful information as it lets you customize squads that are tailor-made for fights on that specific type of map. This feature is a godsend, with the increase in classes and their more specialized nature.

Block the exit!
A soldier can effectively "lock" a doorway if placed on the tile immediately on one side of it. This is because aliens cannot open doors, they can only charge through them. Similarly, ladders and pipes can be "locked" by standing at the top of them; this can be effective for blocking berserkers.

Aliens don't like being flanked.
When an alien is flanked, they are extremely likely to move to get out of the flank - even if this means moving through overwatch and suppression. If you want an enemy to stay put for next turn, it might not be the best idea to flank him this turn.

Supression, Flashbangs, Overwatch and You.
Overwatch shots will not crit unless the soldier/alien has the opportunist perk. Using the grapple hook available on various armors will not trigger overwatch shots. Suppression and flashbangs will cancel overwatch (although the eye indicator will stay up on suppression). The suppressor taking any damage, cloaking, and flashbangs will cancel Suppression.

Drones and their lack of programming.
Drones cannot overwatch, nor can they go through closed doors.

Cyberdicks.
Cyberdisks are nearly immune to critical hits in their folded up form, but not in their attack form. If they go on overwatch upon reveal, it can be a good idea to take a shot taking advantage of the crit bonus. Upon the disk folding up, you can then run a scout to pull the overwatch fire thus tricking the cyberdisk into unfolding again so you can take more shots at it. Using this method can maximize your crit damage potential.

Outsiders.
They can't climb ladders and have no grenades. Beware on landed/crashed UFO missions, triggering the outsider pod has a tendency to make other alien pods converge on your position.

Seekers.
Seekers can only strangle from a decloak by being landed (i.e. no flying defense bonus) on an open tile in one of the 4 main directions of tiles (no diagonals). They seem to preferentially seek out soldiers that are separated from your crew (snipers usually), assaults, and gunners. Seekers ALWAYS know where every member of your team is, they cheat. A decloaking seeker, whether they are attacking or whether you threw a battle scanner, will trigger close combat specialist. Thus, one way to deal with seekers sans battle scanner is to surround an assault with other members of your team so that the seekers can't strangle the assault; when they try to strangle anyone else, the assault trips close combat spec on every seeker that attacks and hopefully kills all of them.

MECs
The MEC grenade launcher and proximity mine launcher can be fired while the MEC is acting as a heavy cover element with "one for all" without breaking the ability. Restorative mist will not stabilize a critically wounded soldier. Proximity mines can be automatically detonated by any other explosive going off with the mine inside the explosive radius. The kinetic strike module can be used to punch through any destructible environment elements; use it to make artificial holes in UFOs.

The KSM does not work with "In The Zone", but the KSM and electro pulse do get damage increases with HEAT ammo (important for goliaths). MECs cannot be strangled and possess partial immunity to acid.

Flush mechanics.
The 50% damage reduction from the perk "flush" is applied BEFORE the HEAT ammo perk. This means that the bonus damage against robot targets is not reduced by 50%.

LOS
Alien line of sight can sometimes be determined: moving into a flanked position will show the shield as red. Moving away from the alien, the point where the shields switch from red to normal marks the limit of the aliens sight.

Chemically assisted capture.
When an alien is affected by Acid and only has a single hitpoint left, he will always refuse to use an action that would otherwise cause it to be triggered and kill him. This can be used to your advantage to prepare unwary invaders for multiple, safe stunning attempts with the Arc Thrower. If an enemy unit is shredded, acid will cause 2 points of damage. Enemies that are shredded, acided, and have 2 hit points left will still move because the AI doesn't take into account the extra shredded damage; thus the alien may move to its death. Be careful when psi-panicking acid affected enemies with 1 HP left, they will often panic move, killing themselves (thus no arc thrower capturing).

Capturing Aliens.
An easy method to capture aliens is to have a unit with packmaster/repair carry an arcthrower and a unit with psi panic. Leave one enemy last such as muton/floater/outsider (or any other low-will enemy), use psi panic on it and make liberal use of the arc thrower until successful.

End Game Armor
Don't just go with the heavy titan armor as always. Archangel armor is one of the best armors available, and not just for that squadsight sniper. You can easily trade 2 hp for the increased mobility and defense bonuses, plus the flying ability and the associated aim bonuses. Your units will rarely miss shots and will not be in danger of getting flanked. You can also laugh at those charging chryssalids and berserkers.

Ethereal Tactics.
Ethereals cannot overwatch. Psi lance is actually the regular attack of the ethereal, and deals damage proportional to will (thus very high damage). Things that reduce the damage of Psi Lance and Rift:
1) Every form of DR including cover.
2) Every 10 points of soldier's will reduce damage by 1.
3) Combat drugs reduce it by 2.
4) Psi inspiration reduce it by 3.
5) Mind merge reduces it by 2.5 (will scale in Beta 14)

Two suppressions can easily reduce the aim close to zero, while also reducing the range of rift. Disabling shot will eliminate the ability to use Psi lance for a turn. Clustered units can be easily wiped out with rift. The ethereal will not use rift if it will get caught up in it as well. Take note that flying units cannot be damaged by rift. Shredding an ethereal first is an ideal way to quickly take it down in one turn with enough firepower. While mind controlling an ethereal will grant rift, in the final mission the volunteer will get rift anyway.