Kill a Special Infected with an exploding barrel.

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

Survive the Cold Stream campaign on any difficulty.

Collect three gifts dropped by Special Infected in Versus Mode.

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

Revive an incapacitated teammate while a Tank is nearby.

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

Destroy a Tank's rock in mid-air.

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

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

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

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

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

Defend yourself at the crashed airliner without taking damage.

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

Collect 100 gas cans in Scavenge.

Collect 15 gas cans in a single Scavenge round.

Make a Survivor drop a gas can during overtime.

Cause 25 gas can drops as a Special Infected.

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

Play 6 Mutations.

Play 5 full games of Scavenge on The Port.