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.
Survive all campaigns on Expert.
Survive a campaign on Expert skill with Realism mode enabled.
Form a team and beat an enemy team in 4v4 Versus or Scavenge.
Cause 25 gas can drops as a Special Infected.
As the Spitter, spit on a Survivor being choked by a Smoker.
Collect 100 gas cans in Scavenge.
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.
Using a Molotov, burn a Clown leading at least 10 Common Infected.
Honk the noses of 10 Clowns.
Cross the bridge finale in less than three minutes.
Defend yourself at the crashed airliner without taking damage.
Kill 10 swampy Mudmen while they are in the water.
Plays games with free weekend players and helps them survive a campaign.
Revive 10 incapacitated Survivors while under the speed-boosting effects of adrenaline.
Finish a campaign using only melee weapons.
Survive the Parish campaign.
Survive the Hard Rain campaign.
Navigate the sugar mill and reach the safe room without killing any Witches.
Survive the Swamp Fever campaign.
Ignite 50 Common Infected with incendiary ammo.
Revive 10 dead Survivors with the defibrillator.
Kill a Tank with melee weapons.
Navigate the impound lot and reach the cemetery safe room without tripping any alarms.
Kill 15 Infected with a single grenade launcher blast.
In a Versus round, leave the saferoom to defibrillate a dead teammate.
In a Survival round, get a medal only using melee weapons.
Kill one of each Uncommon Infected.
Use every melee weapon to kill Common Infected.
Prove you are stronger than Moustachio.
As the Charger, bowl through the entire enemy team in a single charge.
Kill a Charger with a melee weapon while they are charging.
As the Charger, grab a Survivor and carry them over 80 feet.
As the Jockey, ride a Survivor and steer them into a Spitter's acid patch.
As the Spitter, hit every Survivor with a single acid patch.
Collect 10 vials of Boomer vomit from infected CEDA agents you have killed.
Collect 15 gas cans in a single Scavenge round.
As the Jockey, ride a Survivor for more than 12 seconds.
As the Jockey, ride the Survivors twice in a single life.
As the Charger, grab a Survivor and smash them into the ground for a solid 15 seconds.
Kill 100 Common Infected with the chainsaw.
Survive the Dark Carnival campaign.
Rescue Gnome Chompski from the Carnival.
Spread cheer by helping a free holiday player survive a campaign.
Prove you are faster than Moustachio.
Use a bile bomb on a Tank.
Survive the Dead Center campaign.
Deploy an ammo upgrade and have your team use it.
Decapitate 200 Infected with a melee weapon.
Kill a Jockey within 2 seconds of it jumping on a Survivor.
Kill a Spitter before she is able to spit.
Play 6 Mutations.
Kill a Tank only with damage from the original Survivors.
Open 5 foot lockers.
Play 5 full games of Scavenge on The Port.
As the Charger, grab a Survivor and crash them through 8 chairs at the wedding.
Survive The Passing Campaign.
Collect 10 items dropped by a Fallen Survivor.
Using the M60, kill 25 infected without letting go of the trigger.
Play the new Midnight Riders song on a jukebox.
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.
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.
Escape Liberty Mall's Atrium before the first Tank appears
Survive for 10 minutes on any official map in Versus Survival.
As the Hunter, land a 25 damage pounce.
On the concert finale, survive until the helicopter arrives without leaving the stage
Instantly kill a Survivor as the Charger.
Survive The Last Stand campaign on Expert Realism.
Earn a bronze medal on any official Survival map.
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.
Kill 20 Jockeys with the shovel or pitchfork.
Destroy a Tank's rock in mid-air.
Kill a Witch using only a sharp melee weapon, without anyone getting incapacitated or killed.
Destroy 20 gascans as the Spitter.
As the Spitter, spit on a Survivor who is pinned by a Charger.
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
As the Spitter, spit on a Survivor who is pinned by a Hunter.
As the Boomer, vomit on a Survivor without having direct line of sight with them.
Kill the Witch bride with a single shotgun blast on expert difficulty.
Kill a pouncing Hunter with a shotgun.
Rescue three Survivors from a single rescue closet.
With a sharp melee weapon, cut a Smoker's tongue before he ensnares you.
Revive an incapacitated teammate while a Tank is nearby.
If you are reading this achievement, Gabe Newell has successfully launched Gnome Chompski into space.