I'm a 'main' Alien since the beta, and while hunting fully-geared chads in group of three is near impossible, hunting noobs who don't know how to defend themselves is no fun either.
So here you go, some mechanics you need to know if you intend to survive an alien encounter.



Yes, that might be obvious but there's two types of aliens in-game... and many players still confusing the two.

• Humanoid, walks on two legs, still wears something that might have looked like clothes some time ago : this is an infected scientist, is controlled by AI and isn't affected by light in any way. Kill those with regular weapons.
  
• Creature escaped from the film "Alien", walks on four legs (can technically stand up but will move at a snail pace while doing that) : this is what will be referred to as "Alien" for the rest of the guide, player-controlled, sensitive to light but resistant to weapons fire.

In addition to your health and stamina, you have to manage your BPM - too much effort/damage will render you visible to any nearby alien (as a red outline - meaning any experienced alien will know where you are, but also what you're currently doing).

If you're already spotted by the alien, going over the detection threshold is an inconvenience - but if you weren't spotted, change area as soon as you come back under the detection threshold, and keep in mind that the alien may be preparing an ambush.

Sidenote : you can buy a "Cold Blood" neurochip that will raise the detection threshold to 170BPM at the scientist shop. This neurochip will be lost if you die, but if you have difficulties managing your BPM it can be a useful tool - it's always available and only cost 2.145 credits.



As of early-access release, every extraction elevator will arrive two minutes after being called... and will stay there indefinitely until someone use it to extract.
If you intend to extract with an elevator, don't wait until the last second to call it - prepare the extract in advance, roam/loot a bit and come back later : at worst, you'll give a free extraction to a lucky merc team and make their day, at best you'll get yourself a free extract and avoid a two-minutes mexican standoff with a couple of very pissed aliens.

While some of you Mercs may have played a couple Alien rounds, most of the teams I encounter still seems to ignore some of the alien mechanics. Here's a crash course :



In order of energy usage (lowest, and therefore spammable, first) :

• Spit : we can charge and spit acid - that basic ability will always be unlocked, can extinguish flares, and force mercs to use precious healing resources. Upside : it's really, really finicky about hitboxes, and pretty much anything between the alien and the target will intercept the spit - that means "break lines of sight if possible, if not stay behind some cover". Throwing flares in cover also makes it that much harder for the alien to spit on it.
  
• Eggs : Big eggs on the ground, which will spawn a facehugger if you get too close. That facehugger will deal some damage, raise your BPM and reveal you to the alien - the range isn't that great, so a bit of care when going around corners/high covers/doors will keep you out of trouble. If you can, always open opaque doors from the side, in case there's an egg on the other side. Pretty much any regular weapon damage will break the egg.
  
• Gas : Mostly used as area control, the alien can lob a 'grenade' that will spawn a gas cloud. Obviously, don't stay in it - but as long as you're not camping, that one is mostly dangerous when one of your teammates is down or in the elevator. Yes, aliens can gas the elevator : if you know the alien hasn't used that ability in a while, be careful - the only counter there is that the gas 'grenade' will stop at the first solid thing it hits, so staying near the elevator door will keep the gas (mostly) outside and leave a safe spot at the back. The worse thing you can do here is letting the alien gas the whole elevator.
  
• Scan : Emit a pulse that reveal players - as of early access release, it won't reveal solos while there's still groups alive. No counter here, except constant movement and prayers - although it's worth knowing that this ability goes on cooldown on death, so killing the two aliens means you're safe for a while.
  
• EMP : Both the most powerful and weakest ability of the alien - it will burn all active lights (and turrets/drones) for a while, but doesn't affect anything turned off. If your flashlight is affected, call teammates for help if theirs was turned off, because they can use it - while you're doing that, also light a flare : most aliens will back off once they see a flare in your hands, and even the basic flare will kill the alien in under two seconds at melee range.
  
• Scream : A... "wave" ? Supposed to slow and disorient players, but the ability cost is so high that you'll rarely see it - if you do, back off and call your teammates. Strategy is the same as usual : light, light, light. Upside is, if you get hit by the scream you know that the alien energy is pretty much depleted.
  
  
• Heal : The alien can always convert energy to health - while expensive, this ability can quickly become a pain to deal with if there's a live wire nearby (the wounded alien will just retreat to the wire to regenerate energy and health). If you need to stay in the area and know there's an alien nearby, blocking the available wires (by staying close with a flashlight, dropping a glowstick on it or switching on the room light) can severely restrict the alien ability to heal.

Alien spawn (and respawn) with a near-empty energy bar, and eat the eggs scattered around the map to increase their max energy.
Those grow over time - a barely spawned egg will give a (very) minor boost, while a couple eggs there for ten minutes will give enough energy to unlock the EMP. Upside here ? You can break those eggs. Always break the eggs if you see them, as it will slow the alien in early game and gain precious time in the late game.

Aliens regenerate energy slowly, but can also feed on live wires to get a massive boost to their energy regen - the spawns are semi-random ( = limited places they can spawn, but anywhere in that list). If you know you're in an area with live wires nearby, assume the alien have unlimited energy - but they'll often fall back to the wires, so throwing a flare/glowstick on the wire will severely annoy the alien.

Now, for the positive side of things : any damage will block the energy regeneration. While a flashlight at max range will barely do any damage, it will still "starve" the alien until he retreats to the darkness. If you're engaged in a staring contest with an alien, always annoy it when you can (but careful about chasing - if the alien retreats, there's always a good chance a facehugger is waiting at the next corner/door).



The alien can go invisible - great, now you can't see the threat...
...except you can, and you can still deal with it.

• Triggering the invisibility means a couple seconds in animation-lock for the alien - already being in melee range will usually mean that a light source will kill the alien before the invisibility fully triggers (and a surprise room-light is often a death sentence).
  
• The invisibility will block energy regeneration.
  
• Any light damage will be negated, but will drain the energy slowly - if the energy is depleted, the invisibility will break.
  
• Any weapon damage will destroy the energy of the alien while invisible.

The obvious strategy here is to keep someone in charge of lighting up the alien, while another shoots it with regular weapons to drain its energy.

While resistant to weapon fire (although "resistant" is relative when you're bringing fully automatic military weapons to the game), the alien will fry quickly when near a light source.

Shooting the alien with a nail-gun is a telltale sign that you're a beginner, and a free ticket for the nearest graveyard - unless you have heavy weapons at your disposal, always switch to light when dealing with the alien.

The damage from light is dependent on the distance from the source : while a flashlight will only tingle at max range, even the basic flashlight/flare will fry the alien in a few seconds at melee range.



As a Merc, you have quite a few common options available to you :

• Helmet mounted flashlight
  Always available, but won't be useful to survive the alien.
  
  
• Handheld flashlight
  Tool available in the "Basic kit" that you can freely spawn before each round - always bring one with you. This is your common tool to defend against the alien - this should ALWAYS be in your hotbar, ready to go.
  Remember that this is vulnerable to EMP - someone in your group should always keep the flashlight off to use as backup, while taking an EMP to your own flashlight is a sign your should light a flare.
  If you're solo or have difficulties dealing with EMPs, a good strategy is to grab a second flashlight from a dead player - having two flashlights in your hotbar means that you can tank an EMP and still have a functionning flashlight.
  
  
• Flare
  Tool available in the "Basic kit" that you can freely spawn before each round - always bring at least the free pack with you.
  That's a consumable, so it should not be your first choice when dealing with the alien - but you should not hesitate to light one if you're hit by an EMP and don't have other light sources available. No alien will rush you while you're holding a flare - even the basic flare will kill the alien before he can get a couple swipes at you (and if you're at risk of dying from a single swipe, the incoming spit will probably kill you anyway).
  The downside is that the alien can extinguish a flare by spitting on it - even if you're holding it. Especially if you're holding it : the hitbox can be weird when spitting on a thrown flare, but being hit by a spit when you're holding the flare will almost always break it.
  Last tip on the flare : if you're rushed by an alien, lighting a flare will usually send him fleeing - if he did not turn invisible, throwing the flare directly on the fleeing alien will usually deal enough damage to kill him. He goes invisible ? Keep the flare. He flees without invisibility ? Good chance you can kill it.
  
  
• Glowsticks
  Tool available in the "Basic kit" that you can freely spawn before each round - it's probably the most under-used tool against the alien, but I'd recommend you always bring the free pack with you.
  Those won't do much damage to the alien (although even a bit can do the difference to kill it with another light source), but the alien cannot destroy it. Yes, you read that right - there is currently no option for the alien to break glowsticks.
  This makes the glowstick a fantastic tool : if you need to camp somewhere, that's added damage. If you need to retreat, that'll force the alien to either go invisible or take some damage (and if you still have line of sight, weapon damage while invisible will destroy the alien's energy). If there's live wires nearby and you worry that the alien will just heal itself, a glowstick on/under the wire will be a severe pain in the bottom.
  While a glowstick won't do much good if it's your only tool left and the alien is charging at you, it's a very versatile tool to complement other light sources.
  
  
• Room light
  Usefulness will vary depending on where you are on the map, room lights always are a massive threat to the alien - being caught in the center while visible is a death sentence, and dealing with one will require either an EMP (taking a good chunk of energy and sending the EMP on cooldown, meaning you can freely use your flashlights) or going invisible (which can be problematic if some mercs are waiting nearby with weapons to wreck the energy bar and breaking the invisibility while still under the room light).
  Three downsides here : first, it will give away the fact that a human is nearby. It will also eventually turn itself off (flickering, then turning off) and randomly go out when the main generator goes out.
  If you're looting/camping and have easy access to the light button, keeping the room lights off is usually better - while it means that the aliens can roam more freely, it also means that you keep the option to light them up after an EMP is used. You can also keep them up to force an EMP, but you'll either need good group coordination (for the flashlights) or burn a flare (which will eventually deplete your consumables).
  If you're running from one area to another and you know that you're spotted - light everything up, worst case scenario it will annoy the alien, best case you can catch him invisible, destroy his energy bar and fry it with flashlights/flares. If you don't know if you're spotted, I'd recommend lighting up a few rooms, then keeping the rooms dark near your destination - the alien will know someone is nearby, but he won't have your exact location and you'll still have the lights available in case of an EMP.
  
  
• Drone light
  Congratulations, one team member is dead and is now controlling a flying drone. That drone will die in a couple alien hits and will be wrecked by any EMP firing nearby, but can also be a massive annoyance for the alien.
  The drone light will drain its durability, but will also damage the alien and block its energy regeneration - use it for its annoyance factor, and it's a wonderful tool : the alien is retreating ? Too bad, you're still burning with no energy regen. The alien is roaming to flank or prepare its next assault ? Nope, you can either burn or use resources to deal with the drone. It's especially useful since the drone can follow the alien in the vents - to either finish a kill or just keep it at bay.
  That said, the most powerful tool for a drone is its ability to turn on room lights - you can reach lights that would be suicidal for your group to go to (with little to no consequences) and either restrict the alien pathing or outright killing it if he didn't see you coming.
  
  
• Flashbang
  Nothing to say here, flashbangs do not exist. Not at all.
  ...or maybe they do, and it's an insta-kill for any alien caught in the blast. You'll need 13 Rep at the gunsmith to buy the flash grenades, but if you can afford them it's a wonderful tool when you just want that alien gone.
  (Sidenote : The frag grenade will deal less damage to the alien, but are still a decent threat to them)