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.
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.
Kill an enemy by planting a hopper mine.
Break the mini-teleporter in Kleiner's lab.
Use the antlions to kill 50 enemies.
Survive the second turret standoff in Nova Prospekt.
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.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Gain command of a squad of rebels in the uprising.
Kill five enemies with a Manhack.
Kill five enemies with the same energy ball.
Kill an Elite Soldier with his own energy ball.
Steal a Zombine's grenade.
Use flares to light 15 zombies on fire.
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.
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.
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.
Secure the launch doors on missile silo 2.
Kill a Hunter with its own flechettes.
Put the can in the trash.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Save all buildings outside the missile silo from destruction.
Save the missile silo from the Combine offensive.
Beat four Portal advanced maps.
Play a complete round with every class.
Play in a game with seven or more players from your friends list.
Trick an opposing medic into healing you.
Accumulate 25000 heal points as a Medic.
Win 20 games.
Win 2Fort with a shutout.
Successfully defend Dustbowl without giving up a capture.
Get five revenge kills.
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.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
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.
Beat two Portal advanced maps.
Fall 30,000 feet.
Complete Portal.
Make the correct party escort submission position decision.
Jump 300 feet.
Do whatever it takes to survive.
Knock down a turret with another turret.
Play a complete game on every map.
Win Hydro without giving up a capture.
Acquire the fully powered Aperture Science Handheld Portal Device.
Get five kills in a row without dying.
Win Well in 5 minutes or less.
Get the crowbar.
Escape the apartment block raid.
Hit the trashcan cop with the can.
Kill five barnacles with one barrel.
Kill an enemy with a toilet.
Find all lambda caches in Half-Life 2.
Squish every antlion grub in Episode Two.
Find and break every web cache in Episode Two.
Send the garden gnome into space.
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 10 turret kills with a single turret.
Accumulate 1000 total kills.
Successfully defend Gravel Pit without giving up a capture.
Set five enemies on fire in 30 seconds.
Get 25 headshots as a Sniper.
Detach security cameras from the walls.