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 a campaign with no Survivors taking damage from Special Infected.
Survive any campaign on Expert.
Kill 53,595 Infected.
No Survivors take damage after contacting the rescue vehicle.
Play an entire campaign with no Survivors taking friendly fire damage.
Kill 1000 Infected with a mounted machine gun.
As an Infected, incap a Survivor who has entered and left a safe room.
Finish a campaign without ever being healed.
All Survivors complete a campaign without being vomited on.
Sneak past all Witches in a campaign without disturbing one.
Survive the Blood Harvest campaign.
Survive a campaign without being incapacitated.
Survive an entire campaign using only pistols.
Kill a Witch with a single headshot.
Kill all four Survivors in one life while playing as a Tank.
Heal 25 Survivors with a first aid kit.
Drag a Survivor 100 feet with your tongue.
Heal a fellow Survivor when your own health is below 10.
Give pain pills to 10 Survivors.
Shove a Hunter off of a pinned and helpless Survivor.
Light a Tank with a Molotov.
Survive the Death Toll campaign.
Light a Witch with a Molotov.
Punch a Hunter as he is pouncing.
Single-handedly kill a Tank.
Revive 50 incapacitated Survivors.
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.
Shove a Boomer and then kill him without him splashing on anyone.
Headshot a Hunter while he's leaping.
Dole out 5000 total Survivor damage as a Special Infected.
Set 101 Infected on fire.
Kill 10 Smokers as they are pulling helpless Survivors.
Kill a Witch without any Survivor taking damage from her.
Blow up 20 Infected in a single explosion.
Cover four Survivors with Boomer bile at once.
Save another Survivor from a Special Infected while on the ground.
Pounce two different Survivors in one life as a Hunter.
Constrict two Survivors in one life as a Smoker.
Protect any Survivor from an attacking Infected 50 times.
Make 100 headshot kills.
Kill a Tank without it dealing any damage to a Survivor.
Survive the No Mercy campaign.
Beat a campaign with all 4 Survivors.
You or another Survivor take no damage after being vomited on by a Boomer.
Rescue a Survivor trapped in a closet.
Free yourself from a Smoker who has grabbed you with his tongue.
Rescue a Survivor from a Smoker's tongue before he takes damage.
Smoker pull a bile-covered Survivor until you hold him during Crash Course.
Your team incapacitates three Survivors within five seconds in the Crash Course campaign.
Kill 5,359 Infected in the Crash Course campaign.
Win a Versus campaign of Crash Course.
Pounce a Survivor for 25 points of damage in the Crash Course campaign.
Your team wipes all Survivors after the escape vehicle has opened in Crash Course.
Stun a Tank with an explosion in the Crash Course campaign.
Survive the Crash Course Campaign.
Restart the generator within 30 seconds of it shutting off in the Crash Course campaign.
As a Tank hit 20 Survivors with a car in the Crash Course campaign.
Kill a Special Infected with an exploding barrel.
As a Special Infected, incap someone who is trying to sacrifice themselves.
Have Bill sacrifice himself for the team.
Have all 3 generators running at once in "The Sacrifice" finale.
Complete "The Sacrifice".