Squad Composition and Tactics
Soldiers in X-COM are flexible generic soldiers with no pre-assigned role or duties attached to them. Despite this, they will eventually fall into a variety of roles depending on tactical needs.
Until soldiers hit super-soldier status where they can do anything, they will generally fall into particular roles specializing in scouting, sniping, heavy weapons, psionic support, rear commander, etc. There is a lot of overlap between many of these roles, so there's a great degree of flexibility available to you.
The choice of role will largely be dependent on the soldiers' initial stats. However, a soldier's role can change and may change several times in the course of a single battle.
The following sections describe some common roles that your soldiers will fall under, along with some scenarios and tips for these roles.
After securing the landing zone during deployment (making sure all nearby aliens are killed, and establishing a front line), you should expand the secured zone using scouts (see Sweeping the Battlescape). Some commanders prefer using trained scouts (high Reactions and Time Units); others prefer cannon fodder (poor stats). Aliens will often shoot from unseen locations, making high stats irrelevant, and even a soldier with terrible stats can take advantage of the mutual surprise rule.
Tanks make excellent scouts due to their high mobility (70 or 100 TUs, depending on the type) and relative hardiness. They are also easily replaced, unlike veteran troops. However, in the early part of the game, funds are very limited, and replacing a few rookies is far less expensive than replacing a tank.
In terms of equipment, the key is to keep the scout light but functional, so weapons such as Laser Pistol may come in useful for rapidly clearing terrain on most levels either so the scout can move through it, or check there is nothing behind a wall or hedge. HE and Smoke Grenades also tend to be useful, along with Motion Detectors, but items like heavy weapons and First Aid kits are best left to the troops following up where needed.
The soldiers at the front of the transport must perform scout duties during deployment, which is probably the highest-risk stage of combat. Throwing a Smoke Grenade at the base of the ramp before deploying helps to reduce this risk (do not deploy until Turn 2, after the grenade has detonated). For soldiers with flight capability, it may be also a good idea to deploy a second smoke grenade on the equipment pile to provide a screen if they don't intend to deploy at ramp level.
If alien(s) are visible from the front of the transport, they should be killed immediately.
The order on the Soldier screen back at base determines the order of troop placement in the transport. It is unfortunate to have a highly-skilled veteran at the front of the craft, where they are most likely to get killed. One strategy to prevent this is to reserve the first 6-8 soldiers on the list for base defense duty. As your front-most troops gain experience, you can assign these reserves to the transport; they will be placed up front.
XcomUtil can be used to rearrange the order of your troops.
Upon successfully securing the landing zone, the scout will perform recon duties, locating enemy targets so that snipers and heavy weapon specialists can take them down from range.
A sniper is a marksman with a highly accurate weapon who kneels and stay in one spot and attacks enemies from a great distance. They are often kept well behind enemy lines and take up positions that will give them a clear view of much of the playing field - occasionally they will have to reposition themselves to get a better angles or clear obstacles such as buildings. Getting height by climbing onto the roofs of buildings or using a Flying Suit assists this task greatly.
Anybody can fill the role of a sniper, but the best snipers generally begin their career with high accuracy, and hone their skill with continual use. High Firing Accuracy is the main qualification for a sniper as it only has a small window of opportunity to kill. A recruit can start with a maximum score of 70 in this field, yet even troops with a score of 60 can be trained to be worthy snipers.
On their own, Snipers aren't much to go by unless they can see their targets. They are therefore best combined with scouts who seek out and spot enemy targets. Scout/Sniper tactics are among the most effective tactics in the entire game.
There are many sniper friendly weapons available, such as all the rifle types, Small Launcher, the Heavy Plasma and especially the Rocket Launcher. The Blaster Launcher is the ultimate sniper's weapon - and one that needs absolutely no skill on the user's part except for careful waypoint plotting.
The Plasma Rifle, is also a good sniper weapon by having the highest snapshot accuracies in the game. Marksmen with over 100 accuracy can score near perfect snapshots when kneeling. (102 accuracy is needed, to be more specific)
A heavy weapon's specialist consists of a soldier with high strength and firing accuracy, allowing the use of heavy weapons like the Rocket Launcher. Strength is imperative for the heavy weapons user as encumbrance penalties affect rate of fire on account of firing costs being calculated from base TUs rather than encumbrance-modified TUs and therefore heavy weapons duty should be restricted to soldiers that have 40+ Strength. Firing accuracy is important for heavy-cannon users, yet is less important for autocannon, rocket launcher, or blaster launcher users. A loaded Rocket Launcher with 3 Heavy Rockets weighs 42 units total (see Encumbrance and Item Weights).
Heavy weapons generally involve damage on a wide area of effect. This makes them good for clearing terrain and for attacking heavily-armored units such as Cyberdiscs. They are also effective against taking out enemies in cover as even if the shot misses, hitting a terrain piece can result in an indirect hit which still kills.
Although not strictly a "heavy weapon", equipping two or more soldiers with a Small Launcher during the stage of the game when you are trying to capture an alien Navigator, Leader, or Commander is highly recommended (see Research#The Minimum Three). It can also be used as an incredibly effective anti-large terror unit weapon on the easier difficulty levels.
In open terrain (desert, tundra, not very densely populated rural areas) it may be a good tactic to equip a soldier with a flying suit, rocket launcher and possibly more rockets than they can normally carry. Once the perimeter outside the ship has been secured, the soldier can drop surplus rockets on the ground, then rise to maximum altitude and be used as extremely efficient sniper for even quite long distances - the downward angle causes that most rockets that miss the target hit the ground within a few squares away, catching the enemy in the explosion. Once the soldier runs out of rockets, he can land, resupply and take off again.
The role of the Loader (or sometimes referred to as the Ammo Mule in other articles) is to carry ammunition for a heavy weapons specialist.
Ammunition can be heavy in the case of autocannon or rocket ammunition. Usually armed with little more than a pistol, the loader's role is to provide extra ammunition for a heavy weapon trooper, often by throwing it. This can allow for more sustained anti-tank fire. During a ufo assault, the loader does not find much use among blaster-launcher troops on account of the indirect nature of the blaster launcher allowing its wielder to provide support from the transport (and thus from a steady ammo source). In this case, the loader may end up being transferred to grenadier duty if not killed beforehand.
Mind Probe Operators
A support role that is commonly performed by reserve troops that are left in the Skyranger. Any soldier in the safety of the ship can operate a Mind Probe to read the vital statistics of any alien spotted in the field.
Probe operators are made redundant when well trained psi-troopers are available.
A variant of the Heavy Weapon specialist, a grenadier is entrusted a large number of grenades than usual (or as many as the grenadier can carry). This role sets out to exploit the grenade's indirect attack ability to its fullest. Strength is the primary stat to consider, as this controls throwing distance and the soldier's ability to carry grenades without being encumbered. A high initial throwing accuracy also helps although this ability levels up very quickly. Finally, a high reactions score will help prevent a grenadier from getting gunned down by unseen enemies while lighting the fuse. A grenadier can still operate with low reactions if kept behind enemy spotters.
This role is very effective for attacking cover in open terrain, or for taking out clustered enemies. In close-quarters, the blast radius of a grenade can be a liability yet the ability to clear ambush points is still highly valued. The ability to use proximity grenades as an area-denial weapon, electro flares to light up dark battlefields, or smoke grenades to provide cover lends extra versatility to the grenadier. Armed with high explosives, they can even be useful in taking out terror units or negating the existence of barns.
In addition to a wide selection of grenades, a grenadier is often armed with a light sidearm like a Laser Pistol as a fall-back weapon when exhausting all the grenades or for emergencies where a floating enemy cannot be hit by an explosion; however some commanders arm their grenadiers solely with grenades, trusting on the snipers to provide support in the advent of flying enemies. Good protection is also recommended to allow for close range detonations.
Some commanders have their grenadiers arm a set of or all their grenades while in cover and hang on to them for the duration of the battle or until spent. While this makes them exceedingly dangerous to be standing next to (if they are knocked out), it allows grenadiers to rapidly deploy grenades in the middle of firefight without having to waste half of their time setting the grenades. A grenadier could launch a grenade, perform some other action and finally ready the next grenade before the turn ends. A stationary grenadier could deploy up to three grenades at once. While this makes them effective, the initial arming stage puts the grenadier out of the action for a fair number of turns.
A medic is a valuable support role for tending to soldiers that are wounded or unconscious.
A medic is generally an additional role than a role of its own. Any soldier that just so happens to be carrying a Medi-Kit is a field medic, as soldiers cannot use the kit on themselves.
If a soldier is in a critically wounded state and has fallen unconscious, a medic needs to tend to the soldier immediately. If the medic is too far away, and time is not on your side, the medic can employ a variant of the Grenade Relay to get the kit into the hands of a soldier that is closer to the patient.
Guard these well it could mean the difference between Success and defeat.
Also commonly known as Psi-Sponges or decoys.
Before soldiers can be screened scientifically, they can still be equipped to combat Psionics. This applies to soldiers who have not been tested in psionic scenarios or have been shown to be weak against psionic attack. These troops can still be valuable. Anti-psionic soldiers absorb psionic attacks that would otherwise assail stronger minds and eventually Panic them, and can even kill the psionic alien themselves if for some reason it loses control over them. This also works best if armor is available for all troops.
If there are unarmored soldiers i.e. wearing Coveralls, only give psi-weak soldiers Stun Rods and Smoke Grenades. Alternatively, one or more of these soldiers can operate as a heavy weapons crew, as long as the psi-weak trooper is not holding a weapon with ammo at the end of a turn. Other weapons can be handled in this way, but it reduces squad mobility unless two or more can work together, tossing equipment around to each other.
If everyone has at least Personal Armour, psi-weak soldiers can also equip standard Pistols and/or incendiary ammunition. These weapons are effective against Sectoids, while personal armor negates fire damage and allows an agent to withstand several shots from a pistol.
If all your soldiers have at least Power Suits, the psi-weak soldiers can use standard Rifles, Auto-Cannons with AC-HE ammo, and standard grenades with minimal or no risk to other agents. These weapons are highly effective against Sectoids, allowing you to screen a squad against psionics on Medium UFO and Supply Ship raids without taking friendly casualties.
Grunts in Flying Suits can bombard each other with AC-HE and rifle fire throughout the entire mission without a scratch. Flying suits also hold up well against Laser Pistols and Small Rockets from a Rocket Launcher, but use caution with these, as the laser pistol's lethal rate of fire can whittle down even the most heavily armored soldier from the side or rear... and then a small rocket could possibly finish him off, etc. Standard rifles and AC-HE seem ideal since they cause no injury. Standard grenades are much safer, having only a tiny risk of damage to the underside at ground zero.
When raiding sites with Cyberdiscs, it is necessary to use HWPs or some heavier troops known to be psi-resistant. These troops can be "discovered" in Sectoid Medium UFO raids using the equipment configurations above. Those UFOs have less firepower than bases and Battleships, and only one or two psionic officers (who can be captured with stun rods).
Ethereal sites should only be assaulted by known psi-resistant troops and heavily armored HWPs. A small element of unarmed psi-weaklings could be taken on smaller raids to train their mental resistances, but only as a peripheral exercise, along with a much more resistant element to ensure mission success.
After Psi-training, any soldiers with high Psionic Strength (ideally 80+) should be given a Psi-Amp, and kept off the front lines. Other units can be used to spot aliens, and your Psi units can safely attack them from a distance. Once your Psi troops gain high Psionic Skill as well, your squad will become nearly invincible. See Psionics for more details.
Any unit that stays alive and does consistently well in picking up combat experience in ground missions will eventually peak all of his or her attributes.
The difference between Veterans and Rookies
The better stats a soldier has, the less danger you will want to expose him or her to.
Soldiers with the poorest stats should be given the most dangerous duty: for instance, they should be the first unit sent into a UFO - both for training and to protect their senior squad members. As weak soldiers learn at a faster pace than veterans, the experience gained from a being thrown into a dangerous situation and surviving will be extremely beneficial to their careers.
There is safety in numbers: soldiers should generally be moved in groups of 2-4. If one soldier spots an alien, the others can act as snipers. Spotting an alien is useless if it kills your scout and you have no troops available to return fire upon the alien.
An effective four-man fireteam might consist of two riflemen, a heavy weapon, and a "medic" who also acts as a rifleman. The Skyranger allows for up to three four-man fire teams with two spaces left for reserve or command crew. HWPs take up as much space as one fireteam of this sort, but HWPs should be considered force multipliers due to superior armor, mobility, and ammunition capacity.
A highly effective Skyranger crew might look something like this:
1 HWP, either as a front-line armored unit or as support artillery
2 four-man fireteams consisting of 2 riflemen (possibly scout/sniper), 1 rocket or blaster soldier, and 1 rifleman with a medi-kit
2 command crew who can fulfill any of the above roles, usually riflemen but with their own medi-kit and possibly a heavy weapon
The Avenger allows for a wider variety of loadouts.
10-man loadout identical to the above suggested for the Skyranger, but with 3 additional HWPs
14, 18, 22, or 26 soldiers, exchanging 1 HWP for each 4-man team
Note that with 22 or 26 soldiers your capacity for heavy weapons and explosives is drastically diminished. With 18 soldiers there is enough space for the following squad composition:
2 riflemen with 1 rifle, 1 clip, and 2 other items (smoke grenade and electro-flare for example)
1 rifleman/medic with medi-kit in addition to standard rifleman gear
1 rocket/blaster troop with 3 loads and 1 sidearm without ammunition, note a Laser pistol does not need clips, and a plasma pistol, reloads maybe procured from the Aliens. Though at later stages this gets phased out for Heavy Plasma by the Aliens, depending on Rank and Game Difficulty.
The 2 additional soldiers outside of the 4-man teams can be used for nearly any purpose, with 8 items to spare between them.
If more than 18 soldiers are used, they will need to sacrifice effectiveness in exchange for numbers. Substituting laser weapons for the main squad rifles will allow for more equipment. 26 soldiers can only carry one laser rifle and two additional items for a total of 78 items.
The choice of soldiers vs. HWPs is highly dependent on play style. In the early game, tanks are much more expensive than rookies, and funds are tight. However, for players that prefer a highly mobile form of warfare, the increased TUs, energy, and lack of encumbrance means a HWP is able to spearhead assaults, soak up firepower, and disrupt the enemy before your troops finish it off. Later on, tanks come into their own as highly-mobile expendable scouts. Finally, in the early game when psionics are an unknown threat, the HWP/Rocket Launcher is the safest area-effect weapon in that it cannot be mind controlled whereas a mind-controlled soldier with Rocket Launcher could be devastating to your squad.
If you adopt an all-soldier roster, especially on the Avenger (26 soldiers!), you will have to work around the 80-item limit. This will necessitate the use of Laser Rifles as your primary squad weapon, as they do not require ammo clips.
Armor allows troopers to survive longer. However, armor is expensive and can still fail to protect against well-placed heavy plasma shots. Additionally, armor cannot be recovered from dead soldiers. Finally, soldiers are easily replaceable as even a single alien toting a plasma pistol can be sold for a minimum of $104,000 allowing for 2 soldiers and 24,000 to equip them with. Finally, proper use of sniper-spotter tactics, cover, and reaction fire prove a better defense rather than hoping the enemy misses you.
However, such a callous attitude towards your soldiers has its drawbacks. Each soldier lost results in morale penalties to the rest of your troops as well as points lost, which determines the Council's commitment to funding your troops. These penalties will continue to increase as your soldiers gain experience and thus it is imperative your leaders and veteran soldiers be armored to represent the fact.
Early on, one will not have enough resources to armor every soldier and thus priorities must be set. The rear commander should have the best suit available in the advent of an ambush, with remaining suits going to troops in descending order of rank. Rookies and even squaddies can generally go unarmored as their deaths are mitigated against thanks to the commander.
Power Armor will eventually become the de-facto standard for your troops, as elerium stockpiles begin to occur. The Personal Armor that was once standard will eventually find itself being transferred from base to base in an attempt to armor up all garrison troops until 250 power armored suits come about (as well as surpluses in the advent of troop casualties). Flying armor is useful but not cost-efficient to produce in such numbers sadly enough.
Although Flying Suits have the highest armor values, a soldier in mid-air is an easy target. Flying soldiers will also fail to benefit from ground-level smoke cover, such as at the base of the transport. Flying Suits may be of greatest benefit to scouts, who need the increased mobility, as well as snipers who can use flight to acquire optimal firing positions. A mix of Power Suits and Flying Suits is probably best overall for your squad.
Soldier Naming Strategies
One useful strategy is to rename all your soldiers alphabetically. This allows you to see which soldiers will be placed at the front of the transport (arm them with smoke grenades; arm the second row with heavy weapons). To rename soldiers, click on their names while viewing them via the Soldier screen on base.
Another naming strategy is to add stats to their names. Time Units, Reactions, Firing Accuracy, Strength, and Psionic Strength are the most useful stats to display in this fashion. Keep in mind that soldiers' names will have to be updated when they gain stats from experience. A less editing intensive method would be to just assign a general role for the unit and stick to it when arming.
Alternatively the mod UFO Classes renames soldiers for you automatically and thus lets you manage the selection, deployment and training of soldiers via a concept of classes and levels, rather than having to micromanage soldiers based on all their specific stats.