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