Escort Gregori safely through the church cemetery.

Unlocked: 11 Aug 2008 14:50:38

Kill 30 enemies with thrown physics objects.

Unlocked: 11 Aug 2008 14:46:30

Get the Gravity Gun in Black Mesa East.

Unlocked: 11 Aug 2008 04:09:38

Destroy the hunter-chopper in Half-Life 2.

Unlocked: 11 Aug 2008 03:46:52

Get the airboat's mounted gun.

Unlocked: 11 Aug 2008 03:31:40

Get the airboat.

Unlocked: 11 Aug 2008 02:34:13

Kill five barnacles with one barrel.

Unlocked: 22 Jul 2008 14:39:10

Get the crowbar.

Unlocked: 22 Jul 2008 14:16:11

Escape the apartment block raid.

Unlocked: 22 Jul 2008 14:02:27

Jump 300 feet.

Unlocked: 07 Apr 2008 17:08:34

Detach security cameras from the walls.

Unlocked: 07 Apr 2008 16:53:22

Beat all six Portal advanced maps.

Unlocked: 29 Mar 2008 18:03:10

Beat four Portal advanced maps.

Unlocked: 29 Mar 2008 16:46:42

Beat two Portal advanced maps.

Unlocked: 29 Mar 2008 06:56:31

Fall 30,000 feet.

Unlocked: 29 Mar 2008 06:52:47

Complete Portal.

Unlocked: 29 Mar 2008 06:24:57

Make the correct party escort submission position decision.

Unlocked: 29 Mar 2008 05:22:04

Do whatever it takes to survive.

Unlocked: 29 Mar 2008 04:29:47

Knock down a turret with another turret.

Unlocked: 29 Mar 2008 04:11:07

Acquire the fully powered Aperture Science Handheld Portal Device.

Unlocked: 29 Mar 2008 03:25:14

Kill an enemy by planting a hopper mine.

Kill five enemies with a Manhack.

Kill a Combine soldier with his own grenade.

Kill five enemies with the same energy ball.

Kill an Elite Soldier with his own energy ball.

Steal a Zombine's grenade.

Use flares to light 15 zombies on fire.

Hit the trashcan cop with the can.

Put the can in the trash.

Break the mini-teleporter in Kleiner's lab.

Discover the hidden singing vortigaunt cave in chapter Water Hazard.

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

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

Play through Ravenholm using only the Gravity Gun.

Kill 3 enemies using the crane.

Pin a soldier to the billboard in chapter Highway 17.

Defend Little Odessa from the gunship attack.

Destroy six gunships in Half-Life 2.

Cross the antlion beach in chapter Sandtraps without touching the sand.

Use the antlions to kill 50 enemies.

Kill an enemy with a toilet.

Survive the second turret standoff in Nova Prospekt.

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

Survive the generator plaza standoff in chapter Anticitizen One.

Kill all of the snipers in City 17.

Shut down the supression device by disabling its generators.

Survive the rooftop strider battle in the ruins of City 17.

Destroy the Citadel's reactor core.

Find all lambda caches in Half-Life 2.

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

Contain the Citadel core.

Contain the Citadel core without killing any stalkers.

Use the cars to squash 15 antlions in Episode One.

Survive long enough to get on the parking garage elevator.

Help Alyx snipe 30 enemies in Episode One.

Destroy the gunship in the hospital attic.

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

Escape City 17 with Alyx.

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

Kill an acid antlion worker.

Squish every antlion grub in Episode Two.

Find and break every web cache in Episode Two.

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

Defeat both antlion guards outside the White Forest.

Run over 20 enemies with the car in Episode Two.

Survive the Hunter ambush with Alyx.

Defeat the chopper in Episode Two without any misses.

Destroy the Combine cannon in the junkyard.

Find every radar cache in chapter Under The Radar.

Unlock the rocket launcher lambda cache in chapter Under The Radar.

Beat DOG in a race to the White Forest base.

Survive the ambush at White Forest Inn.

Send the garden gnome into space.

Secure the launch doors on missile silo 2.

Save all buildings outside the missile silo from destruction.

Save the missile silo from the Combine offensive.

Kill a Hunter with its own flechettes.

Earn bronze medals on all Portal challenges.

Earn silver medals on all Portal challenges.

Earn gold medals on all Portal challenges.

Accumulate 10 turret kills with a single turret.

Get five revenge kills.

Get five kills in a row without dying.

Trick an opposing medic into healing you.

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

Win 20 games.

Accumulate 1000 total kills.

Win 2Fort with a shutout.

Win Well in 5 minutes or less.

Win Hydro without giving up a capture.

Successfully defend Dustbowl without giving up a capture.

Successfully defend Gravel Pit without giving up a capture.

Play a complete round with every class.

Play a complete game on every map.

Accumulate 25000 heal points as a Medic.

Set five enemies on fire in 30 seconds.

Disintegrate 15 soldiers by throwing them into a Combine ball field.

Gain command of a squad of rebels in the uprising.

Get 25 headshots as a Sniper.