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