Malcontent

5
Escape the apartment block raid.
Lab Rat

5
Acquire the fully powered Aperture Science Handheld Portal Device.
Trusty Hardware

5
Get the crowbar.
Anchor's Aweigh!

5
Get the airboat.
Fratricide

5
Do whatever it takes to survive.
Submissive

5
Put the can in the trash.
Heavy Weapons

5
Get the airboat's mounted gun.
Revenge!

10
Destroy the hunter-chopper in Half-Life 2.
Partygoer

5
Make the correct party escort submission position decision.
Zero-Point Energy

5
Get the Gravity Gun in Black Mesa East.
Heartbreaker

10
Complete Portal.
Hallowed Ground

5
Escort Gregori safely through the church cemetery.
Friendly Fire

5
Knock down a turret with another turret.
Bone Breaker

5
Kill 30 enemies with thrown physics objects.
Where Cubbage Fears to Tread

5
Defend Little Odessa from the gunship attack.
Secret Achievement

5
Continue playing to unlock this secret achievement.
Bug Hunt

10
Use the antlions to kill 50 enemies.
Warden Freeman

10
Survive the second turret standoff in Nova Prospekt.
OSHA Violation

5
Kill 3 enemies using the crane.
Follow Freeman

10
Gain command of a squad of rebels in the uprising.
Deadly Harvest

5
Kill an enemy by planting a hopper mine.
Barnacle Bowling

5
Kill five barnacles with one barrel.
"Radiation Levels Detected"

5
Get through the toxic tunnel under City 17 in Half-Life 2.
Plaza Defender

10
Survive the generator plaza standoff in chapter Anticitizen One.
Watch Your Head!

5
Make it to the bottom of the Citadel's main elevator shaft in one piece.
Hard to Kill

10
Get five kills in a row without dying.
Acid Reflex

5
Kill an acid antlion worker.
Terminal Velocity

5
Fall 30,000 feet.
One Man Army

5
Destroy six gunships in Half-Life 2.
Fight the Power

10
Shut down the supression device by disabling its generators.
Giant Killer

10
Survive the rooftop strider battle in the ruins of City 17.
Singularity Collapse

25
Destroy the Citadel's reactor core.
Containment

5
Contain the Citadel core.
Into the Breach

5
Help Griggs and Sheckley hold off the antlion invasion inside the mine shaft.
Powerhouse Offense

5
Win 2Fort with a shutout.
Elevator Action

10
Survive long enough to get on the parking garage elevator.
Grave Robber

5
Steal a Zombine's grenade.
Twofer

5
Defeat both antlion guards outside the White Forest.
Meet the Hunters

10
Survive the Hunter ambush with Alyx.
What cat?

5
Break the mini-teleporter in Kleiner's lab.
Atomizer

10
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Think Fast!

10
Kill an Elite Soldier with his own energy ball.
Two Points

2
Use DOG's ball to make a basket in Eli's scrapyard.
Attica!

5
Destroy the gunship in the hospital attic.
Escape From City 17

20
Escape City 17 with Alyx.
Gunishment!

5
Destroy the Combine cannon in the junkyard.
Quiet Mountain Getaway

10
Survive the ambush at White Forest Inn.
Secondary Silo Secured

5
Secure the launch doors on missile silo 2.
Lightning Offense

10
Win Well in 5 minutes or less.
Cupcake

10
Beat two Portal advanced maps.
Hot PotatOwned

10
Kill a Combine soldier with his own grenade.
Gordon Propelled Rocket

5
Unlock the rocket launcher lambda cache in chapter Under The Radar.
Defense of the Armament

20
Save the missile silo from the Combine offensive.
Relentless Offense

20
Win Hydro without giving up a capture.
Live Bait

10
Help Alyx snipe 30 enemies in Episode One.
Nemesis

5
Get five revenge kills.
World Traveler

5
Play a complete game on every map.
Blast from the Past

10
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Cache Checker

10
Find every radar cache in chapter Under The Radar.
Flushed

5
Kill an enemy with a toilet.
Master of Disguise

15
Trick an opposing medic into healing you.
Conservationist

5
Kill five enemies with the same energy ball.
Car Crusher

5
Use the cars to squash 15 antlions in Episode One.
Hit and Run

5
Run over 20 enemies with the car in Episode Two.
Targetted Advertising

5
Pin a soldier to the billboard in chapter Highway 17.
Hack Attack!

5
Kill five enemies with a Manhack.
Vorticough

13
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Pedal to the Metal

5
Beat DOG in a race to the White Forest base.
Citizen Escort

15
Don't let any citizens die when escorting them to the escape train.
Impenetrable Defense

10
Successfully defend Dustbowl without giving up a capture.
Head of the Class

5
Play a complete round with every class.
Fruitcake

20
Beat four Portal advanced maps.
Dynasty

10
Win 20 games.
Turret

5
Accumulate 10 turret kills with a single turret.
Zombie Chopper

25
Play through Ravenholm using only the Gravity Gun.
Counter-Sniper

5
Kill all of the snipers in City 17.
Impossible Defense

30
Successfully defend Gravel Pit without giving up a capture.
Long Jump

5
Jump 300 feet.
Grey Matter

5
Get 25 headshots as a Sniper.
Flamethrower

5
Set five enemies on fire in 30 seconds.
Team Doctor

5
Accumulate 25000 heal points as a Medic.
The One Free Bullet

40
Beat Episode One firing exactly one bullet. Grenade, crowbar, rocket, and Gravgun kills are okay!
Vanilla Crazy Cake

30
Beat all six Portal advanced maps.
Pacifist

10
Contain the Citadel core without killing any stalkers.
Payback

10
Kill a Hunter with its own flechettes.
Zombie-que

5
Use flares to light 15 zombies on fire.
Keep Off the Sand!

20
Cross the antlion beach in chapter Sandtraps without touching the sand.
Puttin' On a Clinic

15
Defeat the chopper in Episode Two without any misses.
With Friends Like these...

10
Play in a game with seven or more players from your friends list.
Pinata Party

5
Find and break every web cache in Episode Two.
Little Rocket Man

30
Send the garden gnome into space.
Hardcore

15
Accumulate 1000 total kills.
Neighborhood Watch

35
Save all buildings outside the missile silo from destruction.
Camera Shy

5
Detach security cameras from the walls.
Lambda Locator

15
Find all lambda caches in Half-Life 2.
Get Some Grub

20
Squish every antlion grub in Episode Two.
Basic Science

10
Earn bronze medals on all Portal challenges.
Rocket Science

20
Earn silver medals on all Portal challenges.
Aperture Science

40
Earn gold medals on all Portal challenges.