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.
Survive the Hunter ambush with Alyx.
Kill a Hunter with its own flechettes.
Make the correct party escort submission position decision.
Jump 300 feet.
Accumulate 10 turret kills with a single turret.
Get five revenge kills.
Trick an opposing medic into healing you.
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.
Get 25 headshots as a Sniper.
Get five kills in a row without dying.
Find all lambda caches in Half-Life 2.
Squish every antlion grub in Episode Two.
Find and break every web cache in Episode Two.
Save all buildings outside the missile silo from destruction.
Save the missile silo from the Combine offensive.
Send the garden gnome into space.
Secure the launch doors on missile silo 2.
Run over 20 enemies with the car in Episode Two.
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.
Defeat the chopper in Episode Two without any misses.
Beat all six Portal advanced maps.
Beat two Portal advanced maps.
Beat four Portal advanced maps.
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.
Cross the antlion beach in chapter Sandtraps without touching the sand.
Complete Portal.
Do whatever it takes to survive.
Use flares to light 15 zombies on fire.
Acquire the fully powered Aperture Science Handheld Portal Device.
Fall 30,000 feet.
Knock down a turret with another turret.
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.
Destroy the Citadel's reactor core.
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.
Kill five enemies with the same energy ball.
Kill an Elite Soldier with his own energy ball.
Destroy six gunships in Half-Life 2.
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.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Get through the toxic tunnel under City 17 in Half-Life 2.
Survive the generator plaza standoff in chapter Anticitizen One.
Kill an enemy by planting a hopper mine.
Kill five enemies with a Manhack.
Survive the second turret standoff in Nova Prospekt.
Gain command of a squad of rebels in the uprising.
Kill an enemy with a toilet.
Use the antlions to kill 50 enemies.
Kill 3 enemies using the crane.
Pin a soldier to the billboard in chapter Highway 17.
Defend Little Odessa from the gunship attack.
Kill a Combine soldier with his own grenade.
Play through Ravenholm using only the Gravity Gun.
Escort Gregori safely through the church cemetery.
Kill 30 enemies with thrown physics objects.
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.
Kill five barnacles with one barrel.
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.
Earn bronze medals on all Portal challenges.
Earn silver medals on all Portal challenges.
Earn gold medals on all Portal challenges.
Play in a game with seven or more players from your friends list.
Win 20 games.
Accumulate 1000 total kills.
Accumulate 25000 heal points as a Medic.
Set five enemies on fire in 30 seconds.
Detach security cameras from the walls.