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