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.
Get the crowbar.
Escape the apartment block raid.
Survive the rooftop strider battle in the ruins of City 17.
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.
Find all lambda caches in Half-Life 2.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Gain command of a squad of rebels in the uprising.
Discover the hidden singing vortigaunt cave in chapter Water Hazard.
Play through Ravenholm using only the Gravity Gun.
Get through the toxic tunnel under City 17 in Half-Life 2.
Destroy six gunships in Half-Life 2.
Survive the second turret standoff in Nova Prospekt.
Kill an enemy with a toilet.
Use the antlions to kill 50 enemies.
Cross the antlion beach in chapter Sandtraps without touching the sand.
Pin a soldier to the billboard in chapter Highway 17.
Kill 3 enemies using the crane.
Use DOG's ball to make a basket in Eli's scrapyard.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Kill five barnacles with one barrel.
Break the mini-teleporter in Kleiner's lab.
Kill five enemies with a Manhack.
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