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.
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.
Revive 10 dead Survivors with the defibrillator.
Cause 25 gas can drops as a Special Infected.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Survive all campaigns on Expert.
Collect 100 gas cans in Scavenge.
Kill a Tank with melee weapons.
Kill 15 Infected with a single grenade launcher blast.
Collect 15 gas cans in a single Scavenge round.
Stop the enemy team from collecting any gas cans during a Scavenge round.
Make a Survivor drop a gas can during overtime.
Win a game of Scavenge.
Survive a campaign on Expert skill with Realism mode enabled.
In a Survival round, get a medal only using melee weapons.
Cross the bridge finale in less than three minutes.
Navigate the sugar mill and reach the safe room without killing any Witches.
Rescue Gnome Chompski from the Carnival.
Prove you are faster than Moustachio.
Kill 100 Common Infected with the chainsaw.
Kill a Charger with a melee weapon while they are charging.
As the Spitter, spit on a Survivor being choked by a Smoker.
As the Charger, grab a Survivor and carry them over 80 feet.
As the Charger, bowl through the entire enemy team in a single charge.
As the Jockey, ride the Survivors twice in a single life.
As the Spitter, hit every Survivor with a single acid patch.
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.
Deploy an ammo upgrade and have your team use it.
Finish a campaign using only melee weapons.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Prove you are stronger than Moustachio.
As the Jockey, ride a Survivor for more than 12 seconds.
Survive the Parish campaign.
Survive the Hard Rain campaign.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Survive the Swamp Fever campaign.
Kill 10 swampy Mudmen while they are in the water.
Use a bile bomb on a Tank.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Spread cheer by helping a free holiday player survive a campaign.
Survive the Dark Carnival campaign.
Honk the noses of 10 Clowns.
Defend yourself at the crashed airliner without taking damage.
Survive the Dead Center campaign.
Decapitate 200 Infected with a melee weapon.
Ignite 50 Common Infected with incendiary ammo.
Use every melee weapon to kill Common Infected.
Kill one of each Uncommon Infected.
Kill a Spitter before she is able to spit.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
Play 6 Mutations.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Play 5 full games of Scavenge on The Port.
Collect 10 items dropped by a Fallen Survivor.
Using the M60, kill 25 infected without letting go of the trigger.
Open 5 foot lockers.
Play the new Midnight Riders song on a jukebox.
Knock off the heads of 18 infected with the golf club.
Kill a Tank only with damage from the original Survivors.
Survive The Passing Campaign.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Kill a Special Infected with an exploding barrel.
Have all 3 generators running at once in "The Sacrifice" finale.
Complete "The Sacrifice".
Have Bill sacrifice himself for the team.
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!
On the concert finale, survive until the helicopter arrives without leaving the stage
Kill 20 Jockeys with the shovel or pitchfork.
As the Spitter, spit on a Survivor who is pinned by a Charger.
Destroy 20 gascans as the Spitter.
Escape Liberty Mall's Atrium before the first Tank appears
Earn a bronze medal on every official survival map
Earn a silver medal on every official survival map.
Earn a gold medal on every official survival map.
Rescue three Survivors from a single rescue closet.
Instantly kill a Survivor as the Charger.
Kill the Witch bride with a single shotgun blast on expert difficulty.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Discover the hidden room in the Last Stand campaign
Complete The Last Stand campaign in 13 minutes or less, without any Survivors dying.
Find the golden crowbars hidden in the Left 4 Dead 1 survival maps.
Survive for 10 minutes on any official map in Versus Survival.
Survive for 30 minutes on any official survival map.
Kill a pouncing Hunter with a shotgun.
As the Hunter, land a 25 damage pounce.
As the Spitter, spit on a Survivor who is pinned by a Hunter.
Survive The Last Stand campaign on any difficulty.
Survive The Last Stand campaign on Expert Realism.
Destroy a Tank's rock in mid-air.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Revive an incapacitated teammate while a Tank is nearby.
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.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.