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