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 53,595 Infected.
No Survivors take damage after contacting the rescue vehicle.
Survive a campaign with no Survivors taking damage from Special Infected.
All Survivors complete a campaign without being vomited on.
Survive all campaigns on Expert.
Play an entire campaign with no Survivors taking friendly fire damage.
Kill 1000 Infected with a mounted machine gun.
Survive any campaign on Expert.
Kill all four Survivors in one life while playing as a Tank.
Headshot a Hunter while he's leaping.
Sneak past all Witches in a campaign without disturbing one.
Finish a campaign without ever being healed.
Kill a Witch with a single headshot.
Give pain pills to 10 Survivors.
Save another Survivor from a Special Infected while on the ground.
Light a Witch with a Molotov.
Heal a fellow Survivor when your own health is below 10.
Revive 50 incapacitated Survivors.
Dole out 5000 total Survivor damage as a Special Infected.
As an Infected, incap a Survivor who has entered and left a safe room.
Cover four Survivors with Boomer bile at once.
Survive a campaign without being incapacitated.
Kill an Infected with a single blow from behind.
Drag a Survivor 100 feet with your tongue.
Shove a Boomer and then kill him without him splashing on anyone.
Survive the Death Toll campaign.
Single-handedly kill a Tank.
Punch a Hunter as he is pouncing.
Light a Tank with a Molotov.
Survive an entire campaign using only pistols.
Survive the Dead Air campaign.
Set 101 Infected on fire.
Heal 25 Survivors with a first aid kit.
You or another Survivor take no damage after being vomited on by a Boomer.
Free yourself from a Smoker who has grabbed you with his tongue.
Pounce two different Survivors in one life as a Hunter.
Survive the Blood Harvest campaign.
Kill 10 Smokers as they are pulling helpless Survivors.
Rescue a Survivor trapped in a closet.
Leave a safe room to save an incapped teammate and bring them back safely.
Make 100 headshot kills.
Protect any Survivor from an attacking Infected 50 times.
Survive the No Mercy campaign.
Beat a campaign with all 4 Survivors.
Kill a Tank without it dealing any damage to a Survivor.
Blow up 20 Infected in a single explosion.
Kill a Witch without any Survivor taking damage from her.
Shove a Hunter off of a pinned and helpless Survivor.
Constrict two Survivors in one life as a Smoker.
Rescue a Survivor from a Smoker's tongue before he takes damage.
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.
Pounce a Survivor for 25 points of damage in the Crash Course campaign.
Your team incapacitates three Survivors within five seconds in the Crash Course campaign.
Win a Versus campaign of Crash Course.
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.
Complete "The Sacrifice".
Kill a Special Infected with an exploding barrel.
Have Bill sacrifice himself for the team.
Have all 3 generators running at once in "The Sacrifice" finale.
As a Special Infected, incap someone who is trying to sacrifice themselves.