Containment
Not unlocked yetContain the Citadel core.
Pacifist
Not unlocked yetContain the Citadel core without killing any stalkers.
Citizen Escort
Not unlocked yetDon't let any citizens die when escorting them to the escape train.
Escape From City 17
Not unlocked yetEscape City 17 with Alyx.
The One Free Bullet
Not unlocked yetFinish the game firing exactly one bullet. Grenade, crowbar, rocket, and Gravity Gun kills are okay!
Elevator Action
Not unlocked yetSurvive long enough to get on the parking garage elevator.
Attica!
Not unlocked yetDestroy the gunship in the hospital attic.
Watch Your Head!
Not unlocked yetMake it to the bottom of the Citadel's main elevator shaft in one piece.
Car Crusher
Not unlocked yetUse the cars to squash 15 antlions in Episode One.
Live Bait
Not unlocked yetHelp Alyx snipe 30 enemies in Episode One.
Twofer
Not unlocked yetDefeat both antlion guards outside the White Forest.
Into the Breach
Not unlocked yetHelp Griggs and Sheckley hold off the antlion invasion inside the mine shaft.
Defense of the Armament
Not unlocked yetSave the missile silo from the Combine offensive.
Meet the Hunters
Not unlocked yetSurvive the Hunter ambush with Alyx.
Secondary Silo Secured
Not unlocked yetSecure the launch doors on missile silo 2.
Neighborhood Watch
Not unlocked yetSave all buildings outside the missile silo from destruction.
Pedal to the Metal
Not unlocked yetBeat DOG in a race to the White Forest base.
Gordon Propelled Rocket
Not unlocked yetUnlock the rocket launcher lambda cache in chapter Under The Radar.
Quiet Mountain Getaway
Not unlocked yetSurvive the ambush at White Forest Inn.
Piñata Party
Not unlocked yetFind and break every web cache in Episode Two.
Cache Checker
Not unlocked yetFind every radar cache in chapter Under The Radar.
Get Some Grub
Not unlocked yetSquish every antlion grub in Episode Two.
Puttin' On a Clinic
Not unlocked yetDefeat the chopper in Episode Two without any misses.
Gunishment!
Not unlocked yetDestroy the Combine Autogun in the junkyard.