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This page contains tips and information to improve your performance as a dedicated IAF Marine. Pay attention soldier! Here you will learn tactics, equipment strategy, and weapons strategies. Various warfighter strategies are scattered throughout this wiki, but this resource page collects all relevant entries in one easy to find location. Promotion awaits all good soldiers.

Squad tacticsEdit


A balanced squad with a variety of weapons and support items has the best chances of defeating the Swarm.

  • A Medic is possibly the most vital member of any squad. They can heal damage and cure infestations, which are otherwise death sentences for most marines. A Medic can either dedicate themselves to healing by carrying both the Medical Gun and Heal Beacons, or they can opt to bring a weapon and either means of healing. While any marine can bring a Personal Healing Kit, these can only be used once and are inferior to Medic healing.
  • A Tech is required for quite a few missions that feature hacking. They are also proficient at welding doors open or shut, setting up and dismantling sentry guns.
  • Officers and Special Weapons are never required for any mission. However, an Officer's Leadership can boost the entire squad's power, effectively adding a "fifth man" to the squad. Special Weapons bring superior firepower to any encounter and make great point marines.
  • At least one marine should bring an Ammo Satchel. This becomes a requirement on tougher difficulty levels, as aliens gain more health and thus require more ammo to put down.
  • A few missions require an M868 Flamer Unit to burn down biomass. The game will warn you if you attempt to start such a mission without a flamer.


Democracy has obvious flaws when reaction time is at a premium, such as when your squad is attacked by monstrous aliens who want to tear you limb from limb. It's therefore a good idea to designate a leader who directs the squad's movement so as to keep the squad working together with maximum efficiency. Whenever possible, this leader should be someone with previous game experience and who can use voice communication to pass on directions to the next objective, call for sentry guns to be erected, etc.

Friendly fireEdit

Main article: Friendly Fire

Always be mindful of every marine's position and line of fire. While friendly fire incidents are not too worrisome on Easy/Normal, on Hard/Insane they result in unnecessary damage that needs to be healed, wasted ammo, and decreased damage output. One of the easiest ways to avoid friendly fire is to simply hug the walls. When two marines are moving together down a corridor, if both stay on their respective side, they can cross-fire down the corridor with very little risk of injuring each other.

Stay togetherEdit

The marines should act as a group, rather than scattering across the map and acting independently. Some areas (particularly the first half of Deima Surface Bridge) are particularly unforgiving of teams that split up and run in two or more directions at once.

If you are ever the only marine visible on your screen, then someone has done something very, very wrong, and you should immediately rejoin your team if at all possible. The Swarm aren't going to take it easy on you because you're alone.

Short, controlled burstsEdit

Just because you can empty a magazine in five seconds, doesn't mean you should. Wild, carefree spraying of bullets in sustained full-automatic fire is not only a colossal waste of ammunition, it's a good way to wind up punching a few extra holes in your fellow marines.

Practice, in offline mode, firing controlled bursts of just a few rounds - for most enemies, 6-8 rounds from an assault rifle (half that many for an autogun or pistols) is probably going to be entirely sufficient to turn your target into green slimy giblets.

Equipment tacticsEdit

Hand WelderEdit

  • The hand welder is only useful when there are doors to seal and unseal. Unsealing doors is rarely useful--there are sealed doors on other levels that allow access to better routes or extra weapons, but often the extra bother of defending the welder from the aliens is not worth the advantage given by unsealing the door.
  • Sealing doors, on the other hand, can be a good tactic, especially in crescendo-type moments where the marines must hold a position against an alien onslaught. For example, the Deima Surface Bridge computer is in a room with 5 entrances, but 2 of these are sealable doors and welding them shut can make defending the room much easier. Using adrenaline when the tech hacks overrides the use of defending this particular room altogether, though.
  • Welded doors can be busted down if they take enough damage, regardless of what deals the damage an alien or a marine and most of the time the swarm is eager to burst to the nearest path to you even if that involves breaking a door.

Weapons tacticsEdit

22A3-1 Assault RifleEdit

  • While seemingly weak, the biggest advantage in the 22A3-1 Assault Rifle is in its extensive ammunition capacity. The low damage allows for the rifle to produce a low amount of overkill, making it perfect for cutting down weak swarm while conserving ammunition. User accuracy is also a bit forgiving as a result of the magazine sizes, but as per usual, controlled bursts of fire is preferable to random spraying of bullets. Ammunition is always at a premium in Alien Swarm.
  • Often forgotten, the frag grenades gives the rifle excellent AoE damage and gives it a killer punch against the stronger swarm members. A common tactic is to deploy the grenades against a cluster of swarm who have just broken through a reinforced door resulting in a quick clear. The limited number of grenades is a hefty restriction, so careful selection of opportunities in its use is vital in maximising its effectiveness.
  • The 22A3-1 gains autoaim on enemies that are near active SM75 Combat Flares. Use this to your advantage against small and/or fast-moving enemies, as autoaiming can help conserve ammunition.
  • Finally, the reasonable accuracy of the rifle allows for it to be used as a long ranged weapon should the need arise. Swarm who are hiding behind a chasm are not safe from the reach of the 22A3-1 Assault Rifle.

AVK-36 Marksman RifleEdit

  • While dealing less damage than the Precision Rail Rifle, the AVK-36 excels in quickly dealing damage reliably without the need to time the active reloads in between shots. As a result, the AVK-36 can deal more burst damage against a particular target when the situation gets heated.
  • As expected of sniper weapons, close ranged combat with the AVK-36 is not recommended both due to the limited fire rates and the preciousness of every shot as a result of the limited ammunition capacity. In addition, the ability of the shots to penetrate their target can pose a risk of friendly fire if care is not taken to check beyond the intended target.
  • The enhanced target imaging mode allows for precise shots to be measured due to the zoom image created around the cursor. The marine's movement will be slowed while using this imaging mode, so take care in ensuring that the surroundings are safe enough that moving slower is not a risk.
  • Careful use of the enhanced target imaging mode also allows marines to pick high or low targets off more reliably than the standard aiming reticle. Simply place the crosshairs directly over the target and fire. A single marine with the AVK on the Cargo Elevator can easily deal with the Drones that climb the ceiling slope, leaving his teammates free to take out those that leap in from above.


  • A good strategy for using the chainsaw is to identify places where its weaknesses will not be as pronounced. A stage like Deima Surface Bridge or Timor Station that requires lots of fighting while moving and features multiple possible routes of attack is not a good place for the chainsaw to be used. In contrast, the Cargo Bay elevator is a more acceptable place to use a chainsaw; since the area of play is a small box that the marines must hold, the chainsaw's movement restriction and lack of range are less of an issue. The chainsaw can also work as a welding torch--since it deals high damage without expending ammunition, it is an excellent choice for breaking down a welded door if no torch is available.
  • When fighting Shield Bugs, a good tactic is to go round the back of it while another marine stuns it with the Tesla Cannon. You can then attack its rear with the chainsaw, which is remarkably effective.
  • The Chainsaw can also be used to destroy boulders, instead of the mining laser.
  • The Chainsaw has the largest damage outpt in the game, and is capable of killing the toughest of enemies in moments. It can be used as a backup weapon for the Special Weapons class to take ot single targets without wasting ammo.
  • The Chainsaw is the best weapon at breaking down doors without having to hack or unweld them. Busting the door will also knock it back, crushing any Swarm behind it.
  • The Chainsaw deals maximum damage when it is in the hands of Vegas due to his high Melee Damage Bonus (4/5).

IAF Advanced Sentry GunEdit

  • While the ASG is the most basic of all the sentry weapons, it is a very well rounded piece of equipment that can cover a number of roles. The most obvious is in covering for a team's blind spots while holding out against an incoming attack. Other uses including using it as a decoy against shield swarms, forcing the swarm to either face the sentry gun and get flanked by the squad, or attempt to face the squad and turn its back against the sentry's fire-power.
  • As the ASG is perfectly accurate and does not cause friendly fire, it can be used to provide suppression fire against small and tricky to target swarm, such as the flying swarms and parasites attempting to run in under the cover of its larger brethren.
  • Strategically, the ASG allows for a squad to add an additional gun to the field without having to be burden with the task of actually using it. Since most weapons have approximately the same DPS, deploying an ASG allows a squad to effectively increase their current fire-power by another 'man' while having the advantage that it will not die or panic and parasites can't infect metal.
  • The ASG is not class specific, carry one if you think you won't need a secondary weapon and there may be an opportunity to create a defensive position.

IAF Ammo SatchelEdit

  • Keep an eye on teammate ammo when possible, and drop a kit when someone starts to run low, or when you yourself need ammo. A notification appears when a teammate has run out of ammo entirely, but it is preferable to resupply prior to this point. Teammates can also call for ammo by pressing the number key corresponding to an ammo-carrying squadmate. This creates a bullet icon above their heads that you should look out for.
  • A teammate using the S23A SynTek Autogun or Minigun will need to use up a full ammo kit to resupply the gun.
  • Though ammo need not be deployed in an area being defended, it shouldn't be dropped behind your squad while they are on the move, or else it may go unnoticed and wasted.

IAF Heal BeaconEdit

  • The beacon will split its healing per second amongst all squad members in its area of effect. This means the healing provided to an individual marine when all four marines need healing will be 1/4 the rate and total amount compared to just a single marine. Keep aware of this behaviour and try not to 'share' a beacon that is trying to heal an infested marine as this places the infested marine at risk at not getting enough healing.
  • Heal Beacons are best deployed when squads are required to be stationary (such as in holdout or hacking scenarios), as it is unlikely that they will miss a chance at healing. However, if urgent healing is needed, communicate with your squad to maximise healing by grouping the team around the beacon.
  • Compared to the unlock-able Medical Gun, the heal beacons are capable of healing more damage given the limited provisions, but pays for this by requiring limited movement while healing.
  • Be aware that long ranged swarm will be a pest when healing via the beacons. The larger mortar bugs in particular are a real threat as they will saturate the clustered marines attempting to heal. Secure the area before attempting to heal.
  • Since the medic does not need to do anything to maintain a beacon once it has been dropped, a medic can switch back to a weapon and help kill any swarm. This is great for combat oriented medics since it reduces the amount of time they are taken out of combat.

IAF Medical GunEdit

  • The healing gun is perfect for squads who prefer to heal on the move. The fast healing rate is also perfect for countering the effects of infestation as the infested marine will be cured quicker while they are more likely to stay at a higher health against the parasite's damage.
  • Overall healing capacity is sacrificed in favor of the superior healing speed and the mobility advantages when compared to the stationary beacons. Consider the situation and how you are more likely to heal when picking which equipment to bring to a mission.
  • Although a medic can take both the healing gun and the beacons, keep in mind that a weapon-less marine is incredibly vulnerable and may not able to defend themselves properly against more than one opponent.
  • As the medic has to continuously use the healing gun on the desired target to heal them, this removes the possibility of the Medic being able to assist in holding back or taking down the swarm. It may be worth considering the beacons in addition to better team coordination if you need to do a lot of fighting. As a counter-point, if you mainly heal on the run, there is no comparison to the medical gun.

IAF MinigunEdit

  • If the Autogun is the big brother to the assault rifle, the Minigun is a super-sized personal defence weapon. Sacrificing high endurance suppressive fire for all out 'shoot everything I see', the minigun can turn almost anything in its cone of fire into grape jelly within seconds.
  • Like the PDW, the Minigun suffers from a very high ammunition burn rate, though the Minigun does have 250 rounds in a magazine so it will last a bit longer before you hear the clicks.
  • Owing to its cone of fire, the Minigun is ideal for 'area denial' tactics, declaring and keeping an arc swarm free. Be aware that it sacrifices some damage output compared to the PDWs for this area of effect attack.
  • Also owing to the cone of fire, the Minigun is actually best used in short, sustained bursts against multiple foes rather than attempting to spit out half a dozen bullets as you will tend to want to saturate an area to ensure you get the hits. For targeted attacks, it is best to stick to Autogun, however you can create the same effect by combining the Minigun with Flares. Very effective on harder levels (like insane) where autogun does not cut down the enemy fast enough.

IAF Tesla CannonEdit

  • The Tesla Cannon is a good support weapon for marines behind their allies. It is recommended that Special Weapons characters should not use this as their primary gun, as the DPS is not high enough. Instead, it is recommended for Medics or Techs that want to stay at the back.
  • Due to the the auto-lock on, it can be good for those aliens who try to sneak up behind you. Or for those random swarm you find just hanging around.
  • Remember, this weapon has a lot of ammo (480 shots), so don't use any ammo stashes unless you need to. Save it for someone's assault rifle or autogun.
  • The Tesla Cannon deals next to no damage, leaving it as a support weapon only.
  • As a side note, shooting infested teammates with the tesla gun will slow the infestation rate by about half.

K80 Personal Defense WeaponEdit

  • The biggest thing to note with the K80s is that reloading requires two magazines and not one. Thus, the K80 actually has 80x6 magazines which puts it as having less ammunition than the 22A3-1 Assault Rifle. Its damage does make up for this disadvantage, but a cautious eye must remain on how many bullets you have left.
  • The extreme rate of fire and the damage it causes really mandates that the player controls their fire. Carelessly or needlessly spraying bullets when they are not needed is a big waste. Consider tapping the fire button and select targets which have one or more additional targets behind them so that when the burst kills the first target, the additional bullets in the spray will also strike a mark.
  • True to its name, the K80 is an excellent defensive weapon, but it should not be used as a primary assault weapon as it will burn through its magazine in less than 3 seconds at full auto, giving the swarm an opportunity to close the gap. Used cautiously, the K80 is excellent for medics or techs who may not always be fighting, but when they do, they can contribute a lot to the squad's fire-power.

M42 VindicatorEdit

  • The stopping power of the M42 Vindicator is not to be underestimated. Although it is unlikely to kill more than one target at a time, a close ranged blast is almost certain to kill any non-boss swarm instantly. This is perfect when the Officer is taking the position of point, as the swarm have a tendency to ambush the squad from around corners or from the overhanging ledges.
  • While not recommended, the M42 does have a high enough firing rate that saturating an area with long ranged fire to kill weak targets is possible. However, take note that this will cause considerable overkill and it is not the best use of the M42's ammunition or capabilities.
  • The incendiary grenades add a potent tactical option as the AoE burn is perfect for weakening or outright killing a pack. In the higher difficulties, the combination of an incendiary grenade followed by one or two blasts from the shotgun itself is more than capable of defeating a charge.

M868 Flamer UnitEdit

  • The M868 Flamer Unit is often considered to be the premier weapon to use while on point duty. The generous area of effect as well as the extreme ammunition conservation when using very short puffs of flame allows this weapon to continuously guard the targeted arc against almost any swarm threat, especially the dreaded parasites.
  • While the damage indicated by its stat sheet is extremely low, this damage is incredibly deceptive. The damage caused by the burn is more than sufficient to kill any non-boss type swarm with the briefest of touches. Parasites in particular are virtually instantly killed on contact, which gives this weapon its reputation.
  • While the swarm are burning, they will often stop attempting to attack the player and their team members and will stagger around while burning. Care should be taken, however, as the swarm will often randomly flail around while in their death throes, hitting anyone who strays too close. The movement speed of any swarm who is burning is greatly reduced.
  • The M868 is required for one official campaign map, however it is often considered to be required for any map with a high risk of parasite attacks.
  • As to be expected, the safest position to be in when a M868 Flamer Unit is deployed is to be behind the person wielding it. This is true in both the avoidance of friendly fire, and in the cleansing effect the weapon has against parasite attacks.
  • At higher difficulty levels, the burn the M868 causes will not be sufficient to kill the swarm drones in any reasonable amount of time. While burning, the swarm will still attempt to move towards and attack the marines, albeit very slowly due to their imminent demise. Support fire with the Tesla Cannon or other direct damage weapons is recommended to assist in killing the swarm before they can harm the squad.

Precision Rail RifleEdit

  • Of the two dedicated sniper weapons, the Precision Rail Rifle is certainly the more difficult weapon to handle. The requirement that every shot has to be loaded individually is both a blessing and a curse. When used by someone who can time the active reloads with high certainty, this weapon can achieve a firing rate slightly higher than the AVK-36 Marksman Rifle, thus providing a higher damage per second total as the Precision Rail Rifle hits harder. However, if the shots cannot be reliably loaded, this weapon is significantly weaker as the fire rate is essentially set to the reload speed, which gives it a base firing rate of 0.55 / Sec.
  • As the AVK-36 tends to be more reliable as the user's concentration does not matter for the purposes of the weapon's effectiveness, the Precision Rail Rifle is best used as a specialist weapon against very high value targets that must die very quickly. When boosted using a X33 Damage Amplifier, a single shot is usually capable of killing a target, and two shots fired in quick succession is most certainly all that will be required.
  • The piercing rounds allows a marine to effectively ignore every swarm between themselves and their target for the purposes of lining up the shot. So long as there is a clean line without any terrain obstacles, a marine can be confident that when they pull the trigger, their target will get slugged.
  • The Precision Rail Rifle is best used with a marine who has a Reload Speed Bonus- Crash's bonus is the largest, cutting reload speed to a mere 1.1 seconds.

S23A SynTek AutogunEdit

  • A speciality of the Special Weapons class, the SynTek Autogun is impressive in its ability to shut down a mass of swarm with minimal fuss. Although its base DPS is the same as the 22A3-1 assault rifle, it delivers the same DPS in fewer shots, allowing its impressive magazine capacity to last for longer while dishing out the same amount of pain.
  • Obtaining additional ammunition for the Autogun is incredibly problematic. This weapon requires a full, unused ammunition crate in order to gather enough bullets for a single spare magazine. A squad member taking even a single magazine from a stash will render it impossible for a Special Weapons gunner to replenish their supply of autogun ammunition. Communication and coordination is vitally important to ensure that everyone has the ammunition they need. The Special Weapons player may consider carrying ammo crates in his or her own secondary weapon slot--this makes it possible to ensure that a full ammo crate is available when needed, also providing a healthy supply of extra Autogun ammunition.
  • As the S23A SynTek Autogun slows the movement of the bearer, a backup weapon is recommended when the squad needs to move rapidly. Alternatively, Wildcat's movement bonus helps neutralise this penalty though her proficiency in autogun usage is not as extensive as Wolfe's.

22A7-Z Prototype Assault RifleEdit

  • The 22A7-Z's greatest assets are in its auto-aim capabilities and its stun grenades. While its damage output is not spectacular by any means, it does contribute a surprising amount of damage in steady hands and it is usable at all ranges. The auto-aim allows the weapon to be used to assist team members who are otherwise pinned by the swarm in close combat with reduced risk of friendly fire, though care should always be taken when considering firing anywhere near team members.
  • The stun grenades give this weapon its true calling, and that is in crowd control under any situation and provides a team the ability to flank the shield swarms or to funnel the swarm into a cluster for mass extermination. As the stun grenades do not affect the firer or his/her team members, it can be used in panic situations without fear of unwanted side effects to give the team some breathing space and time to regroup.
  • A handy thing to note is that the 22A7-Z Prototype shares the same ammunition as the 22A3-1 Assault Rifle. When taking both weapons, the maximum spare magazine capacity is increased to 10 magazines, though both weapons draw from this shared pool.

Speed RunsEdit

Main article: Speed Running

Speed Running is an advanced strategy that involves completing a level in the shortest amount of time possible. For more information on how to Speed Run, click the above link to the article.

External linksEdit

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