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.
Spread cheer by helping a free holiday player survive a campaign.
Cause 25 gas can drops as a Special Infected.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
Kill a Charger with a melee weapon while they are charging.
Collect 100 gas cans in Scavenge.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Defend yourself at the crashed airliner without taking damage.
Navigate the sugar mill and reach the safe room without killing any Witches.
Collect 15 gas cans in a single Scavenge round.
Make a Survivor drop a gas can during overtime.
Win a game of Scavenge.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Rescue Gnome Chompski from the Carnival.
Prove you are stronger than Moustachio.
Kill 15 Infected with a single grenade launcher blast.
Finish a campaign using only melee weapons.
Survive the Swamp Fever campaign.
Survive all campaigns on Expert.
Kill a Tank with melee weapons.
In a Survival round, get a medal only using melee weapons.
Revive 10 dead Survivors with the defibrillator.
Survive a campaign on Expert skill with Realism mode enabled.
Survive the Hard Rain campaign.
Survive the Dead Center campaign.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Kill 10 swampy Mudmen while they are in the water.
Use every melee weapon to kill Common Infected.
Survive the Dark Carnival campaign.
Prove you are faster than Moustachio.
Honk the noses of 10 Clowns.
Decapitate 200 Infected with a melee weapon.
Cross the bridge finale in less than three minutes.
Use a bile bomb on a Tank.
Ignite 50 Common Infected with incendiary ammo.
As the Charger, bowl through the entire enemy team in a single charge.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Survive the Parish campaign.
Kill 100 Common Infected with the chainsaw.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Deploy an ammo upgrade and have your team use it.
Kill one of each Uncommon Infected.
As the Charger, grab a Survivor and carry them over 80 feet.
As the Jockey, ride a Survivor for more than 12 seconds.
Kill a Spitter before she is able to spit.
As the Spitter, hit every Survivor with a single acid patch.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
As the Jockey, ride the Survivors twice in a single life.
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.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Plays games with free weekend players and helps them survive a campaign.
Play 6 Mutations.
Play 5 full games of Scavenge on The Port.
Survive The Passing Campaign.
Using the M60, kill 25 infected without letting go of the trigger.
Play the new Midnight Riders song on a jukebox.
Collect 10 items dropped by a Fallen Survivor.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Kill a Tank only with damage from the original Survivors.
Open 5 foot lockers.
Knock off the heads of 18 infected with the golf club.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Have all 3 generators running at once in "The Sacrifice" finale.
Kill a Special Infected with an exploding barrel.
Have Bill sacrifice himself for the team.
Complete "The Sacrifice".
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.
Instantly kill a Survivor as the Charger.
As the Spitter, spit on a Survivor who is pinned by a Charger.
As the Hunter, land a 25 damage pounce.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
Kill 53,599 infected. You made sure the dead won't rise anymore!
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Escape Liberty Mall's Atrium before the first Tank appears
Survive The Last Stand campaign on Expert Realism.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Kill the Witch bride with a single shotgun blast on expert difficulty.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Discover the hidden room in the Last Stand campaign
Earn a silver medal on every official survival map.
Earn a bronze medal on every official survival map
Earn a gold medal on every official survival map.
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
Survive for 30 minutes on any official survival map.
Earn a gold medal on any official survival map.
Earn a silver medal on any official survival map.
Destroy a Tank's rock in mid-air.
Earn a bronze medal on any official Survival map.
Survive The Last Stand campaign on any difficulty.
Revive an incapacitated teammate while a Tank is nearby.
Kill a pouncing Hunter with a shotgun.
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Destroy 20 gascans as the Spitter.
Rescue three Survivors from a single rescue closet.
Kill 20 Jockeys with the shovel or pitchfork.
Survive for 10 minutes on any official map in Versus Survival.
On the concert finale, survive until the helicopter arrives without leaving the stage
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.