Half-Life 2

Kill an acid antlion worker.

Get the airboat.

Disintegrate 15 soldiers by throwing them into a Combine ball field.

Destroy the gunship in the hospital attic.

Kill five barnacles with one barrel.

Find the HEV Suit Charger faceplate in Eli's scrapyard.

Kill 30 enemies with thrown physics objects.

Use the antlions to kill 50 enemies.

Find every radar cache in chapter Under The Radar.

Use the cars to squash 15 antlions in Episode One.

Don't let any citizens die when escorting them to the escape train.

Kill five enemies with the same energy ball.

Contain the Citadel core.

Kill all of the snipers in City 17.

Kill an enemy by planting a hopper mine.

Save the missile silo from the Combine offensive.

Survive long enough to get on the parking garage elevator.

Escape City 17 with Alyx.

Shut down the supression device by disabling its generators.

Kill an enemy with a toilet.

Gain command of a squad of rebels in the uprising.

Squish every antlion grub in Episode Two.

Survive the rooftop strider battle in the ruins of City 17.

If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space. If you did not also receive the achievement 'Manufacturing Ascent', Newell has abandoned his plans to shoot Noam Chomsky into space.

Unlock the rocket launcher lambda cache in chapter Under The Radar.

Steal a Zombine's grenade.

Destroy the Combine Autogun in the junkyard.

Kill five enemies with a Manhack.

Get the airboat's mounted gun.

Run over 20 enemies with the car in Episode Two.

Kill a Combine soldier with his own grenade.

Help Griggs and Sheckley hold off the antlion invasion inside the mine shaft.

Cross the antlion beach in chapter Sandtraps without touching the sand.

Find all lambda caches in Half-Life 2.

Send the garden gnome into space.

Help Alyx snipe 30 enemies in Episode One.

Escape the apartment block raid.

Survive the Hunter ambush with Alyx.

Save all buildings outside the missile silo from destruction.

Destroy six gunships in Half-Life 2.

Kill 3 enemies using the crane.

Contain the Citadel core without killing any stalkers.

Kill a Hunter with its own flechettes.

Beat DOG in a race to the White Forest base.

Find and break every web cache in Episode Two.

Survive the generator plaza standoff in chapter Anticitizen One.

Defeat the chopper in Episode Two without any misses.

Survive the ambush at White Forest Inn.

Get through the toxic tunnel under City 17 in Half-Life 2.

Destroy the hunter-chopper in Half-Life 2.

Secure the launch doors on missile silo 2.

Pin a soldier to the billboard in chapter Highway 17.

Finish the game firing exactly one bullet. Grenade, crowbar, rocket, and Gravity Gun kills are okay!

Kill an Elite Soldier with his own energy ball.

Get the crowbar.

Defeat both antlion guards outside the White Forest.

Use DOG's ball to make a basket in Eli's scrapyard.

Discover the hidden singing vortigaunt cave in chapter Water Hazard.

Survive the second turret standoff in Nova Prospekt.

Make it to the bottom of the Citadel's main elevator shaft in one piece.

Break the mini-teleporter in Kleiner's lab.

Get the Gravity Gun in Black Mesa East.

Play through Ravenholm using only the Gravity Gun.

Use flares to light 15 zombies on fire.