Here is the complete list of unlockable achievements in Aliens: Colonial Marines on the Xbox 360.
There is just one secret achievement to unlock, listed at the bottom.
Now go get your Sigourney Weaver on!
Adaptive Morphology (30) – Upgrade every Appearance slot once for a Xenomorph class
Adios, Muchachos (20) – Gib two enemies at once
Another Bug Hunt (5) – Complete a Challenge
Another Day in the Corps! (20) – Complete Distress
Anytime, Anywhere (20) – Kill a Crusher without it damaging you
Arbitrarily Exterminated (30) – Kill 2179 Xenomorphs
Bad Feeling About This Drop (20) – Complete Sulaco Falls
… But No Cigar (20) – Rescue a teammate from a Close Encounter
Coming Outta the Walls! (10) – Kill a Xenomorph climbing on the walls or ceiling
Distinguished Service Medal (30) – Complete all Challenges
Don’t Count Me Out (5) – Revive a teammate
Dragged Queen (20) – Complete Home
Eat This! (10) – Kill a Xenomorph with a shotgun at very close range
Entry Prohibited (20) – Kill 10 Xenomorphs that are using vents
Field Modified, Kill Certified (20) – Upgrade every slot for a weapon
Field Promotion (10) – Earn Rank 2 as a Marine
Fire Drill (20) – Arm the emergency release and escape in under 2:30 on Sulaco Falls
Game Over, Man! (30) – Complete all Campaign levels on any difficulty
Heavy Lifting (20) – Defeat the Raven in under 1:10 on Soldier difficulty or higher
I Can Handle Myself (40) – Purchase all Upgrades for a weapon
I Feel Safer Already (10) – Have another player join your party
I Heard THAT (25) – Collect all 12 Audio Logs
I Like to Keep These Handy (30) – Collect all 6 Legendary Weapons
I Love the Corps! (40) – Earn Rank 60 as a Marine
It’s a Dry Heat (20) – Kill 3 enemies with a single U4 Firebomb
Just a Grunt (20) – Complete Hope in Hadley’s
Lean and Mean (20) – Earn Rank 20 as a Marine
Let’s Rock! (20) – Kill 10 Xenomorphs in a game with the M56A2 Smart Gun
Love at First Sight (10) – Survive a Close Encounter with a Facehugger
Majority Shareholder (25) – Spend 30 Commendations
Micro Changes in Air Density (10) – Track 100 hostile targets with the Motion Tracker
Mostly Come at Night… (20) – Find Newt’s doll
Need a Deck Of Cards? (5) – Set up a UA 571-C Remote Sentry
No Need For Alarm (20) – Complete One Bullet without setting off the alarm
No Offense (20) – Melee a Lurker that is pouncing towards you
Not Bad For a Human (40) – Complete all Campaign levels on Hardened difficulty
Oorah to Ashes (10) – Collect a Dog Tag
Perfect Killing Machine (20) – Upgrade every Loadout slot for a Xenomorph class
Personal Friend of Mine (10) – Collect a Legendary Weapon
Quoth the Raven (20) – Complete The Raven
Ready to Fry Half a City (5) – Edit a Marine Loadout
Remember the Fallen (30) – Collect all 35 Dog Tags
Secreted from What? (20) – Kill 5 Spitters without being damaged by acid
Short, Controlled Bursts (20) – Defeat all Xenomorphs in the Sulaco hangar bay without them crossing your barricade
State of the Badass Art (50) – Complete all Campaign levels on Ultimate Badass difficulty
Stay Frosty (20) – Complete an entire Challenge category
Still Got a Job to Do (20) – Complete Rampart
Structural Perfection (5) – Edit a Xenomorph Loadout
You Look Just Like I Feel (30) – Upgrade every Appearance slot once for your Marine
Here is the only secret achievement to unlock in the game.
Easter Egg (5) – Find the Easter Egg (Check out my other article for help getting the Easter Egg achievement)
I can’t believe they don’t even have a “RIPLEY!!” achievement.. wtf