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