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