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