Here is the full list of all 45 Aliens: Dark Descent achievements.
Complete Mission 12.
Gather all datapads.
Complete Mission 11.
Kill every Queen during a campaign.
During a campaign, unlock every Xeno Tech.
Advance a Recon to level 10.
Advance a Gunner to level 10.
Complete Mission 10.
Complete Mission 09.
Complete Mission 08.
During a campaign, unlock every weapons.
Complete Mission 07.
Advance a Sergeant to level 10.
Complete Mission 06.
Unlock the APC.
Kill an enemy by using an explosive barrel.
Destroy 4 eggs with one grenade or an RPG shot.
Complete Mission 05.
Complete Mission 04.
Complete Mission 03.
Make the ARC/APC run over an enemy.
Complete Mission 02.
During a campaign, secure 5 survivors.
Have one Sentry kill at least 10 aliens.
Remove a Trait from a marine.
Secure an unconscious marine.
Complete Mission 01.
During a campaign, kill 100 Xenomorphs.
Save a marine from dying of Bleeding.
Kill every Alien of a Massive Onslaught.
Prevent a marine from being Abducted.
Kill an enemy before they detect the squad.
Finish the Prologue.
Finish the game on Medium.
Finish the game on Hard.
Finish the game on Nightmare.
Finish the game on "No One Can Hear Them Scream" mode.
Advance a Medic to level 10.
Advance a Tecker to level 10.
During a campaign, advance each Marine Class to level 10.
Lure a Queen into a Mine.
Save a Marine from being incubated.
Keep all of your marines alive during a campaign.
In any mission, complete at least one objective with only one marine in the squad.
Have a marine with at least 2 Prostheses.