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