Full list of all 99 The Orange Box achievements worth 1,000 gamerscore. It takes around 80-100 hours to unlock all of the achievements on Xbox 360.
Destroy the Citadel's reactor core.
Survive the rooftop strider battle in the ruins of City 17.
Destroy six gunships in Half-Life 2.
Shut down the supression device by disabling its generators.
Kill five enemies with the same energy ball.
Kill all of the snipers in City 17.
Survive the generator plaza standoff in chapter Anticitizen One.
Hit the trashcan cop with the can.
Put the can in the trash.
Escape the apartment block raid.
Break the mini-teleporter in Kleiner's lab.
Get the crowbar.
Beat two Portal advanced maps.
Get through the toxic tunnel under City 17 in Half-Life 2.
Kill five enemies with a Manhack.
Kill an enemy by planting a hopper mine.
Gain command of a squad of rebels in the uprising.
Survive the second turret standoff in Nova Prospekt.
Use the antlions to kill 50 enemies.
Pin a soldier to the billboard in chapter Highway 17.
Kill 3 enemies using the crane.
Defend Little Odessa from the gunship attack.
Play through Ravenholm using only the Gravity Gun.
Escort Gregori safely through the church cemetery.
Kill 30 enemies with thrown physics objects.
Use DOG's ball to make a basket in Eli's scrapyard.
Get the Gravity Gun in Black Mesa East.
Destroy the hunter-chopper in Half-Life 2.
Get the airboat's mounted gun.
Get the airboat.
Kill five barnacles with one barrel.
Accumulate 1000 total kills.
Complete Portal.
Make the correct party escort submission position decision.
Accumulate 25000 heal points as a Medic.
Win 20 games.
Play in a game with seven or more players from your friends list.
Get 25 headshots as a Sniper.
Win Hydro without giving up a capture.
Play a complete game on every map.
Play a complete round with every class.
Win Well in 5 minutes or less.
Set five enemies on fire in 30 seconds.
Trick an opposing medic into healing you.
Win 2Fort with a shutout.
Successfully defend Gravel Pit without giving up a capture.
Get five revenge kills.
Successfully defend Dustbowl without giving up a capture.
Do whatever it takes to survive.
Knock down a turret with another turret.
Accumulate 10 turret kills with a single turret.
Get five kills in a row without dying.
Acquire the fully powered Aperture Science Handheld Portal Device.
Kill a Combine soldier with his own grenade.
Kill an Elite Soldier with his own energy ball.
Steal a Zombine's grenade.
Use flares to light 15 zombies on fire.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Cross the antlion beach in chapter Sandtraps without touching the sand.
Kill an enemy with a toilet.
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.
Fall 30,000 feet.
Jump 300 feet.
Beat four Portal advanced maps.
Beat all six Portal advanced maps.
Earn bronze medals on all Portal challenges.
Earn silver medals on all Portal challenges.
Earn gold medals on all Portal challenges.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Detach security cameras from the walls.