Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Blast From the Past	Defuse a roomful of explosive barrels.
Checking In	Reach the Northern Star.
Combine Harvester	Use the gravity gloves to loot an item off a living Combine soldier.
Consequences	Make your choice.
Cord-Cutter	Shut down the substation.
Crustacean Frustration	Kill the annoying headcrab before it breaks everything.
Dead Giveaway	Loot a corpse.
Deadliest Catch	Use the gravity gloves to intercept an incoming enemy grenade in mid-flight.
Eye of the Geiger	Measure Russell with the Geiger counter.
Flat Note	Kill Jeff.
Freshly Squeezed	Test your grip on a headcrab heart.
Gnome Alone	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.
Gnome Vault of My Own	Bring a garden gnome with you to the Vault.
Good Grub	Feed the snark.
Heart-Breaker Hotel	Get creative turning the power back on.
High Water March	Start climbing the water tower.
Hit and Run	Break out of the Combine prisoner transport vehicle.
Hold Your Liquor	Catch a bottle falling out of a cupboard before it breaks and alerts Jeff.
Indirect Approach	Kill a Combine Heavy while their shield is up.
Little Slugger	Represent yourself with a specific prop on Russell's map.
Mag-Snagger	Catch Russell's ammo magazine before it hits the ground.
Mazel Tov	Pick up and smash fifty glass bottles.
Near-Jeff Experience	Stay close to Jeff for ten seconds (but not too close).
Off the Rails	Stop the prisoner transport train.
On a Roll	Interact with the playground somehow.
Point Extraction	Get to the superweapon.
Pro-Pain	Kill a grunt by shooting their gas tank.
Quaranta Giorni	Enter the Quarantine Zone.
Safe Trip	Use the multitool to hack a tripmine.
Sea Level	Reach the aquatic exhibits.
Smash and Grab	Break open a supply crate with your hands.
Sound Strategy	Escape the distillery without killing Jeff.
Surface Tension	Escape the underground pit.
Sustenance	Receive a tasty treat.
Team Spirit	Bring Russell a bottle of vodka.
Textbook Jinxing	Wake the Strider.
Triple Bypass	Solve the tanker yard's electrical puzzle and escape.
Unbonded	Collect the SMG.
Up in Arms	Install your first pistol upgrade.
Xen Garden	Enter the explosive Xen infestation.
Xen Lootism	Snatch a Xen grenade from its resting place.
Zombie with a Shotgun	Collect the shotgun.