Radiation Levels Detected
Not unlocked yetGet through the toxic tunnel under City 17 in Half-Life 2.
Plaza Defender
Not unlocked yetSurvive the generator plaza standoff in chapter Anticitizen One.
Counter-Sniper
Not unlocked yetKill all of the snipers in City 17.
Fight the Power
Not unlocked yetShut down the supression device by disabling its generators.
Giant Killer
Not unlocked yetSurvive the rooftop strider battle in the ruins of City 17.
Atomizer
Not unlocked yetDisintegrate 15 soldiers by throwing them into a Combine ball field.
Singularity Collapse
Not unlocked yetDestroy the Citadel's reactor core.
Lambda Locator
Not unlocked yetFind all lambda caches in Half-Life 2.
Hack Attack!
Not unlocked yetKill five enemies with a Manhack.
Watch Your Head!
Not unlocked yetMake it to the bottom of the Citadel's main elevator shaft in one piece.
Containment
Not unlocked yetContain the Citadel core.
Pacifist
Not unlocked yetContain the Citadel core without killing any stalkers.
Car Crusher
Not unlocked yetUse the cars to squash 15 antlions in Episode One.
Elevator Action
Not unlocked yetSurvive long enough to get on the parking garage elevator.
Live Bait
Not unlocked yetHelp Alyx snipe 30 enemies in Episode One.
Attica!
Not unlocked yetDestroy the gunship in the hospital attic.
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!
Conservationist
Not unlocked yetKill five enemies with the same energy ball.
Think Fast!
Not unlocked yetKill an Elite Soldier with his own energy ball.
Zombie-que
Not unlocked yetUse flares to light 15 zombies on fire.
Acid Reflex
Not unlocked yetKill an acid antlion worker.
Get Some Grub
Not unlocked yetSquish every antlion grub in Episode Two.