Full list of all 101 Left 4 Dead 2 achievements. It takes around 80-100 hours to unlock all of the achievements in the base game on Windows.
The base game contains 52 achievements, and there are 7 DLC packs containing 49 achievements.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
Kill a Charger with a melee weapon while they are charging.
As the Charger, bowl through the entire enemy team in a single charge.
Cause 25 gas can drops as a Special Infected.
Make a Survivor drop a gas can during overtime.
In a Survival round, get a medal only using melee weapons.
Collect 100 gas cans in Scavenge.
Collect 15 gas cans in a single Scavenge round.
As the Spitter, spit on a Survivor being choked by a Smoker.
As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Win a game of Scavenge.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Revive 10 dead Survivors with the defibrillator.
As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
Defend yourself at the crashed airliner without taking damage.
Kill 15 Infected with a single grenade launcher blast.
As the Charger, grab a Survivor and carry them over 80 feet.
As the Jockey, ride the Survivors twice in a single life.
As the Spitter, hit every Survivor with a single acid patch.
Survive all campaigns on Expert.
Survive a campaign on Expert skill with Realism mode enabled.
Cross the bridge finale in less than three minutes.
Survive the Parish campaign.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Survive the Hard Rain campaign.
Navigate the sugar mill and reach the safe room without killing any Witches.
Honk the noses of 10 Clowns.
Prove you are stronger than Moustachio.
Use every melee weapon to kill Common Infected.
Survive the Swamp Fever campaign.
Kill a Tank with melee weapons.
Ignite 50 Common Infected with incendiary ammo.
Kill 10 swampy Mudmen while they are in the water.
Kill one of each Uncommon Infected.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Decapitate 200 Infected with a melee weapon.
Kill 100 Common Infected with the chainsaw.
Finish a campaign using only melee weapons.
Survive the Dark Carnival campaign.
Rescue Gnome Chompski from the Carnival.
Spread cheer by helping a free holiday player survive a campaign.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Plays games with free weekend players and helps them survive a campaign.
Use a bile bomb on a Tank.
As the Jockey, ride a Survivor for more than 12 seconds.
Prove you are faster than Moustachio.
Deploy an ammo upgrade and have your team use it.
Survive the Dead Center campaign.
Kill a Spitter before she is able to spit.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
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.
Kill a Tank only with damage from the original Survivors.
Knock off the heads of 18 infected with the golf club.
Using the M60, kill 25 infected without letting go of the trigger.
Collect 10 items dropped by a Fallen Survivor.
Open 5 foot lockers.
Play the new Midnight Riders song on a jukebox.
Survive The Passing Campaign.
Have all 3 generators running at once in "The Sacrifice" finale.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Have Bill sacrifice himself for the team.
Complete "The Sacrifice".
Kill a Special Infected with an exploding barrel.
Survive the Cold Stream campaign on any difficulty.
Play a Versus game on Dead Air from start to finish.
Collect three gifts dropped by Special Infected in Versus Mode.
Kill 53,599 infected. You made sure the dead won't rise anymore!
Earn a gold medal on every official survival map.
Earn a silver medal on every official survival map.
Earn a bronze medal on every official survival map
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Destroy 20 gascans as the Spitter.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
As the Spitter, spit on a Survivor who is pinned by a Charger.
Survive for 30 minutes on any official survival map.
On the concert finale, survive until the helicopter arrives without leaving the stage
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
Revive an incapacitated teammate while a Tank is nearby.
Survive The Last Stand campaign on any difficulty.
Survive The Last Stand campaign on Expert Realism.
Destroy a Tank's rock in mid-air.
Discover the hidden room in the Last Stand campaign
Earn a gold medal on any official survival map.
Earn a silver medal on any official survival map.
Earn a bronze medal on any official Survival map.
Rescue three Survivors from a single rescue closet.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Kill 20 Jockeys with the shovel or pitchfork.
Kill the Witch bride with a single shotgun blast on expert difficulty.
Escape Liberty Mall's Atrium before the first Tank appears
Kill a pouncing Hunter with a shotgun.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Instantly kill a Survivor as the Charger.
As the Hunter, land a 25 damage pounce.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Survive for 10 minutes on any official map in Versus Survival.
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.