Left 4 Dead 2 achievements

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

Survive the Cold Stream campaign on any difficulty.

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

Have Bill sacrifice himself for the team.

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

Play the new Midnight Riders song on a jukebox.

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

Kill 10 swampy Mudmen while they are in the water.

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

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

Complete "The Sacrifice".

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