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.
Run over 20 enemies with the car in Episode Two.
Destroy the Combine cannon in the junkyard.
Kill five enemies with the same energy ball.
Hit the trashcan cop with the can.
Cross the antlion beach in chapter Sandtraps without touching the sand.
Kill all of the snipers in City 17.
Find all lambda caches in Half-Life 2.
Use flares to light 15 zombies on fire.
Squish every antlion grub in Episode Two.
Find and break every web cache in Episode Two.
Defeat the chopper in Episode Two without any misses.
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.
Jump 300 feet.
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.
Accumulate 1000 total kills.
Detach security cameras from the walls.
Accumulate 25000 heal points as a Medic.
Beat four Portal advanced maps.
Beat two Portal advanced maps.
Complete Portal.
Make the correct party escort submission position decision.
Contain the Citadel core without killing any stalkers.
Do whatever it takes to survive.
Knock down a turret with another turret.
Win 20 games.
Play a complete round with every class.
Successfully defend Dustbowl without giving up a capture.
Get 25 headshots as a Sniper.
Play a complete game on every map.
Win Hydro without giving up a capture.
Successfully defend Gravel Pit without giving up a capture.
Win Well in 5 minutes or less.
Survive the Hunter ambush with Alyx.
Defeat both antlion guards outside the White Forest.
Get five revenge kills.
Accumulate 10 turret kills with a single turret.
Set five enemies on fire in 30 seconds.
Win 2Fort with a shutout.
Play in a game with seven or more players from your friends list.
Get five kills in a row without dying.
Trick an opposing medic into healing you.
Help Griggs and Sheckley hold off the antlion invasion inside the mine shaft.
Kill an acid antlion worker.
Beat Episode One firing exactly one bullet. Grenade, crowbar, rocket, and Gravgun kills are okay!
Escape City 17 with Alyx.
Don't let any citizens die when escorting them to the escape train.
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.
Use the cars to squash 15 antlions in Episode One.
Steal a Zombine's grenade.
Contain the Citadel core.
Make it to the bottom of the Citadel's main elevator shaft in one piece.
Pin a soldier to the billboard in chapter Highway 17.
Destroy the Citadel's reactor core.
Kill an Elite Soldier with his own energy ball.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
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.
Fall 30,000 feet.
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.
Survive the second turret standoff in Nova Prospekt.
Kill five enemies with a Manhack.
Use the antlions to kill 50 enemies.
Kill 3 enemies using the crane.
Kill a Combine soldier with his own grenade.
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.
Kill an enemy with a toilet.
Use DOG's ball to make a basket in Eli's scrapyard.
Find the HEV Suit Charger faceplate 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.
Get the crowbar.
Break the mini-teleporter in Kleiner's lab.
Escape the apartment block raid.
Put the can in the trash.
Acquire the fully powered Aperture Science Handheld Portal Device.