Full list of all 65 Left 4 Dead achievements worth 1,500 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 3 DLC packs containing 15 achievements worth 500 Gamerscore.
Survive all campaigns on Expert.
Survive any campaign on Expert.
Survive a campaign with no Survivors taking damage from Special Infected.
No Survivors take damage after contacting the rescue vehicle.
All Survivors complete a campaign without being vomited on.
Kill 53,595 Infected.
Kill a Witch with a single headshot.
Single-handedly kill a Tank.
Kill 1000 Infected with a mounted machine gun.
Finish a campaign without ever being healed.
Play an entire campaign with no Survivors taking friendly fire damage.
Sneak past all Witches in a campaign without disturbing one.
Headshot a Hunter while he's leaping.
Survive an entire campaign using only pistols.
Dole out 5000 total Survivor damage as a Special Infected.
Save another Survivor from a Special Infected while on the ground.
Kill all four Survivors in one life while playing as a Tank.
Revive 50 incapacitated Survivors.
Heal 25 Survivors with a first aid kit.
Drag a Survivor 100 feet with your tongue.
Pounce two different Survivors in one life as a Hunter.
As an Infected, incap a Survivor who has entered and left a safe room.
Constrict two Survivors in one life as a Smoker.
Cover four Survivors with Boomer bile at once.
Survive a campaign without being incapacitated.
Survive the Blood Harvest campaign.
Light a Witch with a Molotov.
Give pain pills to 10 Survivors.
Shove a Boomer and then kill him without him splashing on anyone.
Leave a safe room to save an incapped teammate and bring them back safely.
Survive the Dead Air campaign.
Light a Tank with a Molotov.
Set 101 Infected on fire.
Protect any Survivor from an attacking Infected 50 times.
Kill 10 Smokers as they are pulling helpless Survivors.
Survive the No Mercy campaign.
Rescue a Survivor trapped in a closet.
Kill an Infected with a single blow from behind.
Survive the Death Toll campaign.
Beat a campaign with all 4 Survivors.
Blow up 20 Infected in a single explosion.
Rescue a Survivor from a Smoker's tongue before he takes damage.
Kill a Tank without it dealing any damage to a Survivor.
Heal a fellow Survivor when your own health is below 10.
You or another Survivor take no damage after being vomited on by a Boomer.
Make 100 headshot kills.
Free yourself from a Smoker who has grabbed you with his tongue.
Shove a Hunter off of a pinned and helpless Survivor.
Punch a Hunter as he is pouncing.
Kill a Witch without any Survivor taking damage from her.
Win a Versus campaign of Crash Course.
Your team wipes all Survivors after the escape vehicle has opened in Crash Course.
Pounce a Survivor for 25 points of damage in the Crash Course campaign.
Smoker pull a bile-covered Survivor until you hold him during Crash Course.
Kill 5,359 Infected in the Crash Course campaign.
Restart the generator within 30 seconds of it shutting off in the Crash Course campaign.
Stun a Tank with an explosion in the Crash Course campaign.
Your team incapacitates three Survivors within five seconds in the Crash Course campaign.
Survive the Crash Course Campaign.
As a Tank hit 20 Survivors with a car in the Crash Course 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".