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.
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 an acid antlion worker.
Find and break every web cache in Episode Two.
Help Griggs and Sheckley hold off the antlion invasion inside the mine shaft.
Squish every antlion grub in Episode Two.
Defeat both antlion guards outside the White Forest.
Survive the Hunter ambush with Alyx.
Kill a Hunter with its own flechettes.
Use the cars to squash 15 antlions in Episode One.
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!
Steal a Zombine's grenade.
Use flares to light 15 zombies on fire.
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.
Survive long enough to get on the parking garage elevator.
Kill an enemy by planting a hopper mine.
Kill five enemies with a Manhack.
Kill a Combine soldier with his own grenade.
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.
Gain command of a squad of rebels in the uprising.
Kill five enemies with the same energy ball.
Kill an Elite Soldier with his own energy ball.
Kill five barnacles with one barrel.
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.
Find all lambda caches in Half-Life 2.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Destroy the Citadel's reactor core.
Kill 30 enemies with thrown physics objects.
Break the mini-teleporter in Kleiner's lab.
Get the airboat.
Get the airboat's mounted gun.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Destroy the hunter-chopper in Half-Life 2.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Get the Gravity Gun in Black Mesa East.
Use DOG's ball to make a basket in Eli's scrapyard.
Play through Ravenholm using only the Gravity Gun.
Escort Gregori safely through the church cemetery.
Kill 3 enemies using the crane.
Defend Little Odessa from the gunship attack.
Pin a soldier to the billboard in chapter Highway 17.
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.
Play in a game with seven or more players from your friends list.
Accumulate 25000 heal points as a Medic.
Play a complete game on every map.
Play a complete round with every class.
Successfully defend Gravel Pit without giving up a capture.
Successfully defend Dustbowl without giving up a capture.
Accumulate 10 turret kills with a single turret.
Detach security cameras from the walls.
Jump 300 feet.
Win Hydro without giving up a capture.
Win 20 games.
Get 25 headshots as a Sniper.
Get five revenge kills.
Win 2Fort with a shutout.
Set five enemies on fire in 30 seconds.
Get five kills in a row without dying.
Trick an opposing medic into healing you.
Beat all six Portal advanced maps.
Beat four Portal advanced maps.
Win Well in 5 minutes or less.
Beat two Portal advanced maps.
Fall 30,000 feet.
Get the crowbar.
Escape the apartment block raid.
Put the can in the trash.
Hit the trashcan cop with the can.
Complete Portal.
Make the correct party escort submission position decision.
Do whatever it takes to survive.
Knock down a turret with another turret.
Acquire the fully powered Aperture Science Handheld Portal Device.