Full list of all 85 XCOM: Enemy Unknown achievements. It takes around 200 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there are 2 DLC packs containing 35 achievements.
Win a multiplayer match.
Play a multiplayer match against someone with this achievement.
Have a soldier survive every mission in a full game.
Win the game from each of the 5 starting locations.
Beat the game in Ironman mode on Classic or Impossible Difficulty.
Beat the game on Classic difficulty.
Beat the game on Impossible difficulty.
Clear a UFO crash site with one soldier on Classic or Impossible difficulty.
Mind Control an Ethereal. Single player only.
Complete a Very Hard abduction mission in five turns or less on Classic or Impossible difficulty.
Shoot down 40 UFOs.
In a single game, complete every Research Project.
In a single game, complete every Foundry project.
In a single game, shoot down one of each alien craft.
Kill an alien while flying. Single player only.
Win a mission with an all-female squad. Single player only.
Beat the game on any difficulty.
Kill 50 aliens with explosive weapons.
Build the Gollop Chamber.
Make contact with the Ethereal hive mind.
Build a S.H.I.V.
Kill 500 aliens.
In a single game, complete every Autopsy.
Successfully assault an Overseer UFO.
Find a soldier with the Gift.
Build the Hyperwave Relay.
Gain access to the lowest level in your base.
Build a Firestorm.
Acquire 1000 credits in one month.
Build a suit of powered armor.
Get satellite coverage over every country on one continent.
Earn the "Excellent" rating in every performance category on a terror mission.
Recover the Hyperwave Beacon.
Advance one of your soldiers to Colonel rank.
Build a Laboratory.
Uncover the alien base's location.
Kill 150 aliens.
Build a Workshop.
Capture a live alien.
Stun an Outsider.
Fulfill a Council request.
Complete the tutorial mission.
Staff the Research Labs with 80 scientists.
Staff the Engineering Department with 80 engineers.
Launch a Satellite.
Build an item.
Shoot down a UFO.
Build a base facility.
Complete a Research Project.
Complete a mission without losing a soldier.
Take your new ally into the final challenge.
Complete Confounding Light with more than 3 turns left on the timer.
Complete Gangplank.
Complete Confounding Light.
Complete Friends in Low Places.
Beat the game without buying a Squad Size upgrade (Classic+ difficulty)
Field a squad with 4 augmented soldiers, each with a different base ability and win the mission
Field a squad consisting entirely of augmented soldiers and SHIVs (min. 4) and win the mission
Field a squad where all members have at least two modifications (min. 4) and win the mission
Designate a highly decorated soldier as the Volunteer
Kill an enemy as it is psionically attacking you in single player
Kill an unseen enemy detected by a specially modified soldier in single player
Field a fully enhanced squad and win the mission
Kill a Muton Berserker in melee combat in single player
Proc Combat Rush on the entire squad (min. 4)
Use Collateral Damage to blow up a car in single player
Get a Soldier to have 5 modifications in single player
Make certain of the new threat's location
Cause an enemy to suicide
Jump two stories in one move in single player
Have your special-duty soldier kill three enemies in the same mission
Complete Furies
Deploy three tactical subsystems on a single soldier in single player
Deal with the newest global threat
Kill an elite enemy Medic with explosive damage in single player
Complete Deluge
Get at least 4 kills with XCOM Base Security personnel
Eliminate all alien waves
Kill an elite enemy Sniper with one of your own snipers in single player
Eliminate an enemy's shield and kill it on the same turn in single player
Eradicate the infestation
Beat a new special mission without losing any assets
Augment a soldier in single player
Modify a soldier in single player
Stop a squad member from suffocating in single player