Survive the rooftop Strider battle in the ruins of City 17.
Cross the antlion beach in Sandtraps without touching the sand.
Survive the Generator Plaza standoff in Anticitizen One.
Beat Ravenholm using only the Gravgun.
Shut down the supression device by disabling its generators.
Get through the toxic tunnel under City 17.
Survive the second turret standoff in Nova Prospekt.
Break the mini-teleporter in Kleiner's lab.
Disintegrate 15 soldiers by throwing them into a Combine ball field.
Escape the apartment block raid.
Find all of the lambda caches.
Find the HEV Suit Charger faceplate in Eli's scrapyard.
Discover the hidden singing vortigaunt cave in Water Hazard.
Gain command of a squad of rebels in the uprising.
Get the Airboat.
Get the Airboat's mounted gun.
Get the crowbar.
Get the Gravity Gun in Black Mesa East.
Kill five enemies with Manhacks.
Kill all of the snipers in Follow Freeman.
Kill five barnacles with one explosive barrel.
Destroy the Hunter-Chopper.
Use the Antlions to kill 50 enemies.
Kill 3 enemies using the crane.
Kill an enemy with a toilet.
Destroy six Gunships
Make a basket in Eli's scrapyard.
Pin the soldier to the billboard with the Crossbow in Highway 17.