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