So since there were people who think that HQ that HQ sucks or HQ is OP, I've written a guide about this side. Of course you can add your own HQ tactics if you have any. This guide was written by me, mostly using my knowledge and some from mevitar's knowledge. 
I hope it will serve good purpose for you.
General information about Headquarters:
Headquarters or simply HQ is one of the hardest factions in terms of gameplay. HQ is about making mass of infantry units and of course stealth assaults. Infantry units play vital role in the gameplay and it is almost impossible to play without them as HQ and this sub-faction also supports them with various support powers. Due to the fact that Shadow Tank belongs to this faction it is also possible to make stealth based attacks, ambushes. Of course this doesn’t mean that you should run into a base and destroy everything in it, because that is impossible if your opponent plays well.
Gameplay information about the HQ unique units and support powers:
Infantry:
T3
Stalker:
Stalker is an anti-structure and anti-infantry support infantry. They are quite expensive and in sheer numbers they can tear apart any kind of structure in seconds. Stalker has the ability to immobilize enemy infantry from great distance, which allows the player to easily eliminate heroes such as Siegfried and Volkov with Invaders or Basilisks. However, they can’t damage infantry and they must be defended always. Stalker takes 2 passenger slots in tranports, so it is quite expensive to do a Driller APC ambush with them. He is immune to dog bite.
Rahn:
Rahn is the genetically manipulated hero of Headquarters. Rahn is one of the most agile and powerful heroes in the game. His weapon can deal great damage to both armor and structures. He mutates enemy infantry into Brutes, but there are exceptions (for example Dogs, Dreamweavers, Chitzkoi, Volkov and other cyborgs), this means that they will simply die from one shot. Furthermore every infantry, but the exceptions turns into Brutes, if they are in the line of the shot. He is immune to dog bite. While Rahn is very powerful it is advisable to keep him safe. With the Driller APC you can transport him with a single Stalker to do ambushes and to elimininate for example a structure.
Units:
T1
Opus Custom Tank:
Opus is the basic tank for HQ. While it is a basic tank it can carry an infantry (which doesn’t take more than 1 passenger slot) and that infantry operates a second barrel (if the infantry isn't a dog nor a Dreamweaver). Opus with an infantry is a less armored, faster version of the Qilin Tank and that means that it can do lots of damage to both armor and structures. Since it can be used as a transport you can do special strikes on the enemy with this tank. Placing engineers in them can be used to safely capture tech structures and to capture enemy buildings. Opuses can weaken enemy buildings and if you weaken them enough you can capture that building with only 1 engineer. Of course, this tactic doesn’t work on uncapturable ones.
T2
Shadow Tank:
Shadow Tank uses the power of stealth and this means that the enemy never knows from where they will attack. It’s dissolver beam is powerful against both armor and infantry, but it doesn’t do much damage against buildings, so it isn’t advisable to attack bases with them (with a great number of Shadow Tanks it is possible to sneak in less defended points and attack). While it only reveals itself when attacking Shadow Tank has fragile armor so it isn’t advisable to attack with them straightforwardly. They are very good for ambushes and harassing miners. They can be used as stealth detectors in your army.
T3
Colossus:
Colossus is an anti-armor and anti-air heavy armored unit. Colossus can deploy into it’s anti-air mode which is quite effective against air units, but it can’t attack ground units while deployed. It is really good anti-armor too, but it shouldn’t be used alone, because base defenses and infantry can tear it apart easily. Colossus offers good defense to you army from both armor and air.
Aerial Fortress Irkalla:
Mental Omega 3’s most iconic unit. While this masterpiece looks almost unbeatable it mustn’t be used alone. She can’t handle heavy anti-air spam alone. She must remain well protected from enemy fire. She has two type of weapon: dissolver beams and imploders. The dissolver beams are very effective against infantry and can be used for anti-air purposes too. The imploders shoot „fireballs” which will follow the target until they hit it or run into an obstacle. The fireballs explodes, which deals damage not only to the targeted unit, but units nearby the targetted one too. Build it only if your army is always ready to protect her, because losing her is a great loss, since she costs very much. Excellent for base defense and giving an all round defense for your army. If used properly she can even outrange anti-air base defenses.
Support Powers:
Kinetic Barrier:
Kinetic Barrier is a free support power which increases the resistance of the affected infantry to enemy fire. This can save your infantry from being doomed if used in good time. Using it on a spam of Brutes for example can be deadly for your opponent.
Geneburst:
Not much can be said about this one. It can be used to weaken enemy infantry and if they are already damaged enough then you can turn them into loyal Brutes.
How to play as HQ:
When the warfactory is built then you should build 2 Stingers/Gatling Tanks (it would be better to use Stingers, because with engineers you can counter Terror Drone attacks) and 2 Opus Custom Tanks. Use these for defending your base from various units. After these units are ready build 3-4 Ghost Miners to have a good income. After the War Factory you should build a Radar Spire to gain access to Brutes and Shadow Tanks. Train Brutes and when the building of the Miners has been finish you should build some Gatling Tanks, Opus Tanks and Stingers, after this you should start to build Shadow Tanks. Good thing about HQ is that they can stay at T2 relatively long. Build War Factory and Barracks or if you want to tech up quickly then Pandora Hub after Radar Spire. With Shadow Tanks you can harass your opponent's Miners and they are also good for assassinating units or even a whole army (if you know from where to attack). It is also recommended to train Dreamweavers and Duneriders. Dreamweavers can create distractions between enemy units while Duneriders are excellent anti-infantry, anti-structure infantry with the ability to detect cloaked units. When you reach T3 then build a Driller APC, train Rahn and a Stalker and start to build Cloning Vats. You can do surprise attacks with Rahn + Stalker + Driller APC combo. When Cloning Vats is ready it is advisable to train Brutes again, but this time train Epsilon Adepts, Stalkers and Archers too. In the War Factory, build at least 5 Colossuses (it isn't a big problem if you build more of them) and at least 5 Basilisks (same what I said for Colossus). The final unit for your army should be Irkalla. This army is more then enough to be able to use Irkalla properly. Now let's see some tactics.
Driller APC ambush: With Rahn and a Stalker you can take out valuable structures such as Battle Labs and War Factories with ease. You can also eliminate tech structures with them, which you don't want to attack with your forces.
Miner harassment: With a decent amount of Shadow Tanks you can turn enemy miners into ashes in seconds.
Opus rush: Building 3 Engineers and putting them into 3 Opus Custom Tanks can be used for several purposes. One is that they are quite effective against armor and structures. Other thing is that you can unload the engineers whenever and wherever you want and capture that structure (you can even capture a CY if you are fast enough). You can also weaken structures with Opus Tanks so you will need only 1 engineer to capture that one.
Irkalla as a base defense destroyer: Not many people know this, but Irkalla can slightly outrange basic air defenses so she can safely destroy them. Of course in order to accomplish this, you have to place Irkalla where she begins to attack them. Although you still need to protect here from anti-air units. Because of this she can also eliminate those base defenses, which are guarded by anti-air defenses.
Basilisks + Stalkers: This one just like the previous one needs a good army to be able to accomplish it. Stalkers can destroy anti-air defenses, allowing Basilisks to be able to move closer to the enemy's base and attack it. It is advised to keep Irkalla, Colossuses and Archers near to them.
Kinetic Barrier + Archers/Brutes: When the enemy would approach you with threatening units you can use Kinetic Barrier on a group of Brutes so they will die harder from those units. If that unit is an air one (for example Thor Gunship) you can use this tactic against it with Archers.
Countering:
As United States:
Since Abrams Tank can't handle Brute spam alone you'll need other tactics. Using Mercury strike on your opponent's forces is very good, although Mercury reloads a bit slowly. Tanya + Stryker IFV gives a mobile Mercury, which is good against infantry. Basilisks and Irkalla can't be countered by Aeroblazes. It is also good to use many Navy SEAL-s because they can get rid off Brutes efficiently. Basswaves can be used too, although they aren't very efficient against heavy forces of infantry.
As European Alliance:
This side is one of the sides, which can counter HQ easier than others Siegfried, Prism Tank are good infantry butchers. Thor Gunship is also efficient in terms of killing infantry, also it can kill Irkalla quickly, but don't rush with them, if the enemy's Irkalla is well defended.
As Pacific Front:
Pacific Front has several units which are good against infantry spam. Hailstorms can easily get rid of them from high distances. Blizzard Tank can also do this although it doesn't have as much range as the Hailstorm. Have Battle Fortresses with 4G.GIs in each of them, because they kill air units very quickly.
As Russia:
Wolfhounds won't help against an experienced HQ player, because of the Colossuses and Archers. In fact Russia has disadvantage against a well prepared HQ army, but Russia has a good unit: SCUD Launcher. SCUD Launchers in big numbers can deal with mobs of infantry and armor with ease. It is advisable to focus them more when you play against HQ as Russia. Have Wolfhounds and other forces to defend them.
As Latin Confederation
The Latin Confederation has lots of units which can easily deal with infantry spam. First is the hero, Morales. The second unit isn't used that much as I've seen and it is a big mistake. This unit is the Buratino. Buratino can deal with masses of infantry from distance easily, while you can harass the armored units with Morales. Keep Drakuvs in the base, because they can abduct enemy infantry and that infantry will be yours, forever. Of course you can defend your forces with the good old Catastrophe + Desolator combo.
As China
China has more disadvantage against HQ than any other factions. Sentinels aren't very efficient against Irkalla. Nuwas can be countered by either Epsilon Adepts or Brutes. Eradicators and Gyrocopters can help against infantry. In fact, if you manage to build many Gyrocopters you can deal with Irkalla relatively quickly.
As PsiCorps
The only things that help against HQ are Gehennas and Libra. Gehennas can take out Irkalla and Libra can be used for harassment. Basilisks can help against infantry spam. Magnetrons can immobilize Rahn and the Stalkers so your units can deal with them.
As Scorpion Cell
Scorpion Cell has Basilisks and Plague Splatters. Both of them are efficient against infantry, but it isn't necessary to use both of them at the same time. Oxidizer + Gatling Tank can deal with Irkalla and other air units with seconds. Scorpion Cell units are also fast so they can ignore the forces and attack the base directly. This tactic works well with Tyrants.
As Headquarters
Stalemate detected.
Edited by Petya, 15 January 2014 - 04:27 PM.
