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.
Accumulate 1000 total kills.
Squish every antlion grub in Episode Two.
Find and break every web cache in Episode Two.
Save the missile silo from the Combine offensive.
Save all buildings outside the missile silo from destruction.
Secure the launch doors on missile silo 2.
Send the garden gnome into space.
Beat DOG in a race to the White Forest base.
Find every radar cache in chapter Under The Radar.
Survive the ambush at White Forest Inn.
Run over 20 enemies with the car in Episode Two.
Unlock the rocket launcher lambda cache in chapter Under The Radar.
Destroy the Combine cannon in the junkyard.
Defeat the chopper in Episode Two without any misses.
Survive the Hunter ambush with Alyx.
Kill a Hunter with its own flechettes.
Defeat both antlion guards outside the White Forest.
Help Griggs and Sheckley hold off the antlion invasion inside the mine shaft.
Kill an acid antlion worker.
Don't let any citizens die when escorting them to the escape train.
Contain the Citadel core without killing any stalkers.
Use flares to light 15 zombies on fire.
Use the cars to squash 15 antlions in Episode One.
Beat Episode One firing exactly one bullet. Grenade, crowbar, rocket, and Gravgun kills are okay!
Escape City 17 with Alyx.
Destroy the gunship in the hospital attic.
Help Alyx snipe 30 enemies in Episode One.
Survive long enough to get on the parking garage elevator.
Steal a Zombine's grenade.
Contain the Citadel core.
Make it to the bottom of the Citadel's main elevator shaft in one piece.
Find all lambda caches in Half-Life 2.
Hit the trashcan cop with the can.
Put the can in the trash.
Kill all of the snipers in City 17.
Cross the antlion beach in chapter Sandtraps without touching the sand.
Pin a soldier to the billboard in chapter Highway 17.
Kill 3 enemies using the crane.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Kill five barnacles with one barrel.
Use DOG's ball to make a basket in Eli's scrapyard.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Play through Ravenholm using only the Gravity Gun.
Destroy the Citadel's reactor core.
Kill an Elite Soldier with his own energy ball.
Kill five enemies with the same energy ball.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
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.
Survive the generator plaza standoff in chapter Anticitizen One.
Get through the toxic tunnel under City 17 in Half-Life 2.
Kill an enemy by planting a hopper mine.
Gain command of a squad of rebels in the uprising.
Break the mini-teleporter in Kleiner's lab.
Survive the second turret standoff in Nova Prospekt.
Kill five enemies with a Manhack.
Kill a Combine soldier with his own grenade.
Kill an enemy with a toilet.
Use the antlions to kill 50 enemies.
Defend Little Odessa from the gunship attack.
Escort Gregori safely through the church cemetery.
Kill 30 enemies with thrown physics objects.
Get the Gravity Gun in Black Mesa East.
Destroy the hunter-chopper in Half-Life 2.
Accumulate 25000 heal points as a Medic.
Accumulate 10 turret kills with a single turret.
Get 25 headshots as a Sniper.
Get the airboat's mounted gun.
Get the airboat.
Play in a game with seven or more players from your friends list.
Win 20 games.
Trick an opposing medic into healing you.
Set five enemies on fire in 30 seconds.
Get five kills in a row without dying.
Play a complete round with every class.
Play a complete game on every map.
Win Hydro without giving up a capture.
Win 2Fort with a shutout.
Successfully defend Dustbowl without giving up a capture.
Successfully defend Gravel Pit without giving up a capture.
Win Well in 5 minutes or less.
Get five revenge kills.
Get the crowbar.
Escape the apartment block raid.
Detach security cameras from the walls.
Earn gold medals on all Portal challenges.
Earn silver medals on all Portal challenges.
Earn bronze medals on all Portal challenges.
Jump 300 feet.
Fall 30,000 feet.
Beat all six Portal advanced maps.
Beat four Portal advanced maps.
Beat two Portal advanced maps.
Complete Portal.
Knock down a turret with another turret.
Make the correct party escort submission position decision.
Do whatever it takes to survive.
Acquire the fully powered Aperture Science Handheld Portal Device.