User:Ditto51/Ditto51's Guide to Impossible in XCOM: Enemy Unknown (EU2012)

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This is my guide on how to complete XCOM: Enemy Unknown on impossible, which is extremely hard because of the sharp increase to Floaters and Thin Men with their health increasing from 4 to 6 as well as Sectoids increase to 4 from 3.

Major Recommendations on the Tactical Side

  • Never ever Dash unless you are 100% sure that you won't wake up an alien pack.
    • Even when bringing your sniper forward so that he can get a shot in on the Outsider is a fairly bad idea as you could accidently wake it up if your sniper manages to find the correct line of sight pattern through the door
  • Put your men on Overwatch once they have all moved once so that you can take a shot at any aliens you wake up wit your last man
  • Don't be afraid to sell equipment but be ready to learn when to stop selling certain corpses
  • If you need only a couple credits then sell some Elerium, Alien Alloys or Weapon Fragments

The First Month

Starting Country

While you may want to go for North America for the cheaper aircraft, it probably won't be as beneficial when compared to Africa's All In bonus, Europe's Expert Knowledge and South America's We have ways.

The All In Bonus grants you a 30% increase to your funding, which will suffer greatly from the lack of satellites being launched

The Expert Knowledge bonus makes your Labs and Workshops cheaper and cheaper to maintain, helping to decrease research time along with workshop time, prices and adjacent workshops grant your a 7% rebate.

We Have Ways is another good bonus that makes your interrogations and autopsies be completed faster. This bonus however is located on the easiest continent to cover, with only two countries, so it may be easier to cover South America with satellites when you get the chance rather than starting there.

The First Mission

Your grenades will be your best friend for the duration of the first mission (and beyond), they may no longer be able to oneshot kill the Sectoids but they can weaken them and remove their cover, and thus allow other members of your squad to finish them off with the Rifle or Pistol.


Well placed Grenades can also take away the cover of thee Sectoids while also harming them to the point that they are oneshot killable with your pistol. And with that you should be able to win the opening mission with few casualties.

Back at Base

Xeno-Biology is a must do first research project followed by the Arc Thrower because of the need to capture a live alien and complete the Alien Base Mission in order to bring the panic levels down enough so that you don't lose eight countries within the first three months.

A Medikit is also a must build as well as at least one satellite, more if you can afford it.

Supports and Assaults

Your support soldiers should be put on ice until you research Plasma Weaponry, or at the very least the Laser Rifle

You Assaults soldiers should be put on ice until you research armour for them to wear, thus allowing them to survive the Sectoid Plasma Pistol which basically has a guarrentted hit after the assault had run and gunned to get closer to an alien he is shooting.

First Abduction

If by chance one of the rewards is a high level Heavy then go for it, the heavies will just about save your life. If not then go for Scientist, you'll need them in order to complete the necessary research quicker.

Consider taking along a rookie instead of a support because of the possibility that the Rookie will be promoted to a heavy who are your new best friends with the ability to hold two grenades and fire both a normal rocket (oneshot Floaters, Thin Men and Outsiders.) and a shredder rocket (oneshot Sectoids). Taking rookies instead of Assault soldiers before you get armour because of the relative probability that if you run and gun you are going to get yourself killed, or activate more alien packs.

If an alien that has been activated has moved off screen, DO NOT give chase. Overwatch and wait for it to run back, otherwise you risk waking up more squads before you have finished dealing with the other squad.

Always remember that you are not penalised for damaged – destroying cover does not effect any monthly income, so use your grenades to blow the Sectoid cover away and leave them open to the rest of your squad to shot them in the face.

Outcome of Research and Engineering

If the Arc Thrower research is completed

Before UFO Assault

If your lucky then you can have both Xeno-Biology and the Arc Thrower researched before the first UFO appears (Always a Small Scout). You do not need to have the Alien Containment built in order to house and capture an Outsider.

Small Scout Crash

Treat this as a normal mission and take out the squads one by one, once both Sectoid Squads are down, wake up the Outsider, use a grenade to lower his health and destory his cover before running up with an Arc Thrower and stunning him. Granting you the ability to research it the second you get a Sectoid.

If the Arc Thrower research and Alien Containment are completed

Before UFO Assault

If you're lucky then you can have both Xeno-Biology and the Arc Thrower researched and also the Alien Containment before the first UFO appears (Always a Small Scout). With both are completed then you can take two Arc Throwers and two grenades.

Small Scout Crash

When you come across your first squad of Sectoids you'll want to take out two and use one of the grenades to weaken a Sectoid before you run up to him and stun him with the Arc Thrower. Then before assaulting the UFO, you should find and deal with the second squad of Sectoids. And then follow the same method as above to capture the Outsider, and so you can get onto the alien base within the first or second month.

Nothing is completed

Deal with the UFO as if it were an abduction mission, use your grenades wisely and take out the Outsider on the same turn that you meet him.


After you finish the research of the Arc Thrower and the live aliens you should begin researching into Lasers, and if you got a live Sectoid then you will get the Beam Weapons Research credit allowing for them to be completed faster than normal.

Slingshot or Random Council Mission

Pros and Cons of the Slingshot Council Missions
Pros Cons
Early access to the OTS No Panic Reduction
A Lieutenant class heavy, who can be very useful with their oneshot kill rockets
Early access to Mutons and their Plasma Rifles (Not LPR)
You get a Battleship*

*It is not worth researching the things you retrieve from the battleship.

Pros and Cons of Normal Council Missions
Pros Cons
Panic Reduction No extra weapons other than the Light Plasma Rifle
that can be taken from a stunned Thin Men
No Mutons, only Thin Men No Battleship

Either way if you stun a Thin Man then you get to research the LPR and as a result you get to research the Plasma Cannon, essentially skipping both the Phoenix Cannon and the Laser Cannon.

The Mission


  • A sniper with Squad Sight
  • A Heavy
  • At least one Arc Thrower with 2 doses
  • One Frag grenade.
  • Preferably a Support with the Sprinter Ability so that you can stun the Muton.

Normal Council Mission

Treat it normally, use grenades to destroy cover and then take a shot with one of your soldiers, use full cover and complete the objectives.

Slingshot – Friends in Low Places

All Based off of starting view The first turn should be spent moving your men into place and hiding Zhang behind the full cover gravestones and get him to use his head down ability. Meanwhile get your sniper onto the left hand side of the stairs right in the corner and order him to go into Overwatch with his Pistol. Your other soldiers should go into overwatch with their pistols in a way that allows them very little chance to miss.

Thin Man Stun

Don't OVERWATCH heavies

Have a solider close by to the small rectangle of of gravestones on the other side of the statue to your left, in order to stun the Thin Man (UFO Technology Research Credit) after it has been weakened by Pistol fire from your other soldiers.

A heavy is probably best for this as it frees up your pistol wielding soldiers to attack the Thin man that drops.
When you stun the Thin Man, remember that there is still another that drops towards the middle of the map
Muton Stun

As you move up the left hand side of the map ensure that your men are in a position to flank the Thin Man that drops on the left hand side of the statue at the top of the stairs in a way that allows you to flank him just by activating his drop but leaving most of your men on the bottom floor. Send your stunner into the middle of the map, preferably not your heavy because you'll need his rocket later. You can either leave your sniper where he is or bring him up onto the upper platform where he'll have a better view on the graveyard.

Deal with the enemies as you see fit while keeping Zhang towards the back of the map out of harms way. When the Muton drops, organise your men so that your stunner can reach the muton when it runs forwards, have your heavy ready with his rocket launcher to knock off 6 health, and then have your fourth soldier sat in place with frag grenade. Throw the frag and launch the rocket in any order before running forwards with your stunner in order to stun the now 1 health muton.

It is completely up to you as whether or not you can afford to lose a soldier or not, which will decide whether to place him out of cover or in cover to stun the muton.

Complete the Mission

Just continue going through the mission slowly, using your sniper to take out the exposed enemies that drop it. Once you think all aliens are dead, bring Zhang forwards (albeit slowly) keep him in cover and use his head down ability whenever he is in half cover. Using your soldiers to take out one alien is far easier in these missions than abductions because you rarely come up against three aliens at once.

Aftermath of first Council Mission

If you did Slingshot or any of your soldiers level up to Sergeant

If you have the cash then begin building the Officer Training School, and as soon as it is completed buy the Squad Size I improvement.

If you did not meet the above criteria

If you didn't then you are going to struggle with the next part of the game. Your main priority once you have the ability to make lasers is split to personal preference, eg:

  • You either begin researching into the Nanofiber Vests;
  • Begin researching better laser weaponry;
  • Or begin to ready yourself for the Base Assault.

The Second Abduction

Still only Sectoids, with maybe some Thin Men possibly. When choosing this mission take into account the reward. You will need scientist in order to finish your armour and advanced lasers before the second Slingshot mission or you take on the Alien Base. Engineers could be a possibility if you feel like you need more, like you need a second uplink. You're about to get your monthly funding, so there is no point in accepting the $200 reward, nor is there any point in accepting any soldiers, especially if they're support soldiers.

You may also look at what continants their on. If you have one of SAmerica and Africa, but during the first you stopped one in SAmerica, then don't worry about SAmerica because odds are it won't get enough panic increase for a country to leave.

After Action

Congratulations, you've survived the first month of the alien invasion. By this point you probably have 4 panicking countries, so if one of them is on your starting continent, in Asia or North America then leave it. Really you want to go and attempt to cover one of the panicking countries in a place you like so if you started in Europe, save Africa or SAmerica. If in Africa then save Europe or SAmerica. And if you're in SAmerica then save Europe of Africa.

For those of you who started in SAmerica, Africa should be a priority and for those of you who started in Africa, SAmerica should be your priority. And if you started in Europe then your screwed for the most part, that is unless you manage to get away with one of those being the places that you decided to prevent the abduction in.

Preparing for a new Month

Begin constructions of uplinks, labs and workshops that you can afford, ensure you have sold anything that is useless (Because of how common place Sectoids are for the first few months, you can get away with selling their corpse for Money). The Thin Men continue to appear in council missions for the entire game and are commonly the only units found on them, so knock yourself out and sell their corpse. Any satellites should be launched and new ones placed on order (around three or more) along with a new uplink and Access Lift.

The Second Month

Planning for the month ahead

Begin by ensuring that you have satellites under-construction along with uplinks to aid them. You'll probably need around 4 by the end of the month if you choose the Slingshot, but if you choose the normal Missions then you can get panic reduction at the end of the month. The Terror Mission in the middle of the month will probably also aid in the panic reduction methods if you can deal with the power hyped Zombies.

Sell Sectoid corpses for the next month, continue selling Thin Men corpse for the rest of the game, and begin selling Floaters when you get them. This will grant you some extra cash for whatever you need. Never ever sell Erlium or Weapon Fragments, but Alien Alloys are free game in small quantities.