If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.

Kill a Spitter before she is able to spit.

Kill a Jockey within 2 seconds of it jumping on a Survivor.

Deploy an ammo upgrade and have your team use it.

Survive the Dead Center campaign.

Kill one of each Uncommon Infected.

Revive an incapacitated teammate while a Tank is nearby.

Use a bile bomb on a Tank.

Survive The Passing Campaign.

Survive the Dark Carnival campaign.

Kill 100 Common Infected with the chainsaw.

Decapitate 200 Infected with a melee weapon.

Ignite 50 Common Infected with incendiary ammo.

Survive the Hard Rain campaign.

Survive the Parish campaign.

Survive the Swamp Fever campaign.

Complete "The Sacrifice".

Use every melee weapon to kill Common Infected.

As the Spitter, hit every Survivor with a single acid patch.

Kill 10 swampy Mudmen while they are in the water.

Kill a pouncing Hunter with a shotgun.

Destroy a Tank's rock in mid-air.

Using a Molotov, burn a Clown leading at least 10 Common Infected.

Survive the Cold Stream campaign on any difficulty.

Collect 10 items dropped by a Fallen Survivor.

As the Jockey, ride a Survivor for more than 12 seconds.

Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.

Have Bill sacrifice himself for the team.

As the Jockey, ride the Survivors twice in a single life.

As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.

As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.

Kill 15 Infected with a single grenade launcher blast.

Open 5 foot lockers.

Knock off the heads of 18 infected with the golf club.

Survive The Last Stand campaign on any difficulty.

Kill a Tank only with damage from the original Survivors.

With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.

Earn a bronze medal on any official Survival map.

Play the new Midnight Riders song on a jukebox.

Spread cheer by helping a free holiday player survive a campaign.

As the Spitter, spit on a Survivor being choked by a Smoker.

Honk the noses of 10 Clowns.

As the Charger, grab a Survivor and carry them over 80 feet.

Navigate the impound lot and reach the cemetery safe room without tripping any alarms.

Kill a Charger with a melee weapon while they are charging.

Kill a Tank with melee weapons.

As the Charger, bowl through the entire enemy team in a single charge.

As the Boomer, vomit on a Survivor without having direct line of sight with them.

Collect three gifts dropped by Special Infected in Versus Mode.

As the Spitter, spit on a Survivor who is pinned by a Hunter.

Navigate the sugar mill and reach the safe room without killing any Witches.

Using the M60, kill 25 infected without letting go of the trigger.

Rescue Gnome Chompski from the Carnival.

Have all 3 generators running at once in "The Sacrifice" finale.

Kill a Special Infected with an exploding barrel.

Revive 10 dead Survivors with the defibrillator.

Win a game of Scavenge.

Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.

As the Spitter, spit on a Survivor who is pinned by a Charger.

Stop the enemy team from collecting any gas cans during a Scavenge round.

Earn a silver medal on any official survival map.

Prove you are faster than Moustachio.

Prove you are stronger than Moustachio.

Cross the bridge finale in less than three minutes.

Defend yourself at the crashed airliner without taking damage.

Collect 15 gas cans in a single Scavenge round.

Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.

Play a Versus game on Dead Air from start to finish.

Instantly kill a Survivor as the Charger.

Earn a gold medal on any official survival map.

Finish a campaign using only melee weapons.

Escape Liberty Mall's Atrium before the first Tank appears

Play 6 Mutations.

Rescue three Survivors from a single rescue closet.

Make a Survivor drop a gas can during overtime.

Discover the hidden room in the Last Stand campaign

Survive a campaign on Expert skill with Realism mode enabled.

Plays games with free weekend players and helps them survive a campaign.

Survive all campaigns on Expert.

On the concert finale, survive until the helicopter arrives without leaving the stage

Kill 53,599 infected. You made sure the dead won't rise anymore!

Collect 100 gas cans in Scavenge.

In a Survival round, get a medal only using melee weapons.

Cause 25 gas can drops as a Special Infected.

In a Versus round, leave the saferoom to defibrillate a dead teammate.

As the Hunter, land a 25 damage pounce.

Play 5 full games of Scavenge on The Port.

As a Special Infected, incap someone who is trying to sacrifice themselves.

Form a team and beat an enemy team in 4v4 Versus or Scavenge.

As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.

Kill the Witch bride with a single shotgun blast on expert difficulty.

Survive for 30 minutes on any official survival map.

Kill 20 Jockeys with the shovel or pitchfork.

Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.

Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.

Destroy 20 gascans as the Spitter.

Survive The Last Stand campaign on Expert Realism.

Earn a bronze medal on every official survival map

Earn a gold medal on every official survival map.

Earn a silver medal on every official survival map.

Survive for 10 minutes on any official map in Versus Survival.