Full list of all 46 Aliens: Fireteam Elite achievements worth 1,115 gamerscore. It takes around 100-120 hours to unlock all of the achievements in the base game.
The base game contains 42 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 4 achievements worth 115 Gamerscore.
Returned 39 pieces of intel on a single character.
Fill every slot in a perk board.
Eliminate 1000 Synthetics.
Heal your fireteam with an aid kit 100 times.
Eliminate 10000 Xenomorphs.
Complete 25 successful Challenge runs.
Finish the "Only Way to be Sure" Campaign.
Collected 25 attachments on a single character.
Collected one attachment of every type on a single character.
Complete a mission without using aid kits, ammo crates, or consumables.
Level a weapon to four stars.
Finish the "Gift of Fire" Campaign.
Eliminate 300 Pathogen.
Kill 50 enemies with explosive barrels or pods.
Finish the "Giants in the Earth" Campaign.
Do a successful Challenge run.
Equip three attachments on a single weapon.
Finish the "Priority One" Campaign.
Change your hat and outfit.
Get grappled five times in the same mission.
Equip a colorway and decal onto a gun.
Finish a mission on Intense Difficulty.
Finish a mission on Extreme Difficulty.
Finish a mission on Insane Difficulty.
Finish all Campaigns on Standard Difficulty.
Finish all Campaigns on Intense Difficulty.
Finish all Campaigns on Extreme Difficulty.
Finish all Campaigns on Insane Difficulty.
Open 50 hidden caches.
Level a Kit to Rank 8.
Level five Kits to Rank 8 on a single character.
Level 30 weapons to four stars on a single character.
Eliminate 2000 elite enemies.
Kill 1000 enemies with fire.
Kill 1000 enemies with electricity.
Collect 20 emotes on a single character.
Collect 20 hats on a single character.
Collect 40 decals on a single character.
Collect 40 weapon colors on a single character.
Use 500 consumables.
Complete 50 missions without anyone being downed.
Complete a mission on Intense Difficulty or above without anyone taking friendly fire damage.
Finish the "Promise of a Flower" Campaign.
Return 48 pieces of intel on a single character.
Destroy 50 explosive spore pods with Weapons or Abilities.
Finish a mission on Hardcore 10 Difficulty.