- Trick, not Treat
Kill 5 Halloween Specimens with any gun without reloading
- Keep Those Sneakers Off the Floor!
Kill 20 Stalkers with Explosives.
- Quarter Pounder With Ease
Turn 5 Fleshpounds into Giblets.
- Hide and go Puke
[2013 Summer] Destroy all the Pukey the Clown dolls
- The Big Hunt
Kill a Circus Scrake with a Crossbow.
- Arcade Gamer
[2013 Summer] Complete the Pop the Clot, the Strong Man and the Grenade Toss games
- Taking Down the Big Top
Kill 4 Circus Zeds in 1 ZED time chain with a Melee weapon.
- Sparring with a Master
Kill a Circus Gorefast with a Melee weapon.
- Seeing Double
Kill 5 Circus Crawlers with a Bullpup in one wave.
- Ringmaster
Kill the "Ring Leader" (Circus Patriarch)
- I Like To Watch
Aquire 5 Minutes of "Zed-Time".
- Clearing Clown Alley
Kill 5 Circus Bloats in one game.
- Guardian Assault Protector
Protect the ringmaster during the defense mission so that he does not get hit more than 15 times
- Extended Motion Protector
[2013 Summer] Protect the Ringmaster during the escort mission so that he does not get hit more than 15 times
- Elephant Gun
Land the killing blow on a Circus Fleshpound with a Pistol.
- Small Hands
Kill 3 Circus Clots in a wave with the Lever Action Rifle.
- Soul Collector
Free the souls of the 25 Gnomes hidden on Hillbilly Horror in 1 game
- Homer's Heroes
Kill 100 Sirens.
- Self Medicator
In Co-op Mode, Use Syringe on Yourself 100 Times.
- Flaming Hell, That was Close
As Firebug, kill the Husk with the Flamethrower before he hurts anyone.
- Random Axe of Kindness
Kill 15 Specimens with a Fire Axe in a Single Wave.
- Experimentimillicide
Kill 1,000 Specimens.
- Philanthropist
Give 1,000 Pounds to Teammates who have 50% of Your Cash or Less.
- Straight Rush
Kill the Patriarch Before he has a Chance to Heal.
- British Superiority
Kill a zed each with both the Bullpup and FN-Fal
- Historical Remnants
Kill 6 Zeds with one magazine on an MKb42, without reloading
- Social Outburst
Kill 8 Specimens with One Grenade.
- Too Close For Comfort
Finish off a Fleshpound using a Melee Attack.
- Experimenticenticide
Kill 100 Specimens.
- It's Not Easy Being Greasy
Cause a Specimen to Die by Luring them into Bloat Acid.
- Pub Crawl
Win a Long Game on West London on Normal Difficulty.
- Lord of the Manor
Win a Long Game on Manor on Normal Difficulty.
- Lab Cleaner
Win a Long Game on Biotics Lab on Normal Difficulty.
- Chicken Farmer
Win a Long Game on Farm on Normal Difficulty.
- The Boss
Win a Long Game on Offices on Normal Difficulty.
- The Long War
Complete a Long Game on all 5 Core Maps on Normal Difficulty.
- Hot Cross Fun
Kill 25 Burning Specimens with a Crossbow.
- Thin-Ice Pirouette
Complete 10 Waves when the Rest of your Team has Died.
- Mr. Perky
Get All of your Perks up to Level 5.
- Hard Pub Crawl
Win a Long Game on West London on Hard Difficulty.
- Duke of the Manor
Win a Long Game on Manor on Hard Difficulty.
- Cattle Farmer
Win a Long Game on Farm on Hard Difficulty.
- Hard Boss
Win a Long Game on Offices on Hard Difficulty.
- Lab Assistant
Win a Long Game on Biotics Lab on Hard Difficulty.
- The Hard War
Complete a Long Game on all 5 Core Maps on Hard Difficulty.
- Suicidal Pub Crawl
Win a Long Game on West London on Suicidal Difficulty.
- Emperor of the Manor
Win a Long Game on Manor on Suicidal Difficulty.
- Alligator Farmer
Win a Long Game on Farm on Suicidal Difficulty.
- Mad Boss
Win a Long Game on Offices on Suicidal Difficulty.
- Lab Professor
Win a Long Game on Biotics Lab on Suicidal Difficulty.
- The Completely Suicidal War
Complete a Long Game on all 5 Core Maps on Suicidal Difficulty.
- Tin Man
Win a Long Game on Foundry, on Normal Difficulty.
- Steel Worker
Win a Long Game on Foundry, on Hard Difficulty.
- Man of Steel
Win a Long Game on Foundry, on Suicidal Difficulty.
- Gone Mental
Win a Long Game on Bedlam, on Hard Difficulty.
- Complete Barking
Win a Long Game on Bedlam, on Suicidal Difficulty.
- Squirrel King of the Dark Forest
Win a Long Game on Wyre, on Normal Difficulty.
- Raccoon King of the Dark Forest
Win a Long Game on Wyre, on Hard Difficulty.
- Bear King of the Dark Forest
Win a Long Game on Wyre, on Suicidal Difficulty.
- Long, Hot Summer
Complete a Long Game on all 3 Summer 2009 maps on Normal Difficulty.
- Summer of 2009
Complete a Long Game on all 3 Summer 2009 maps on Hard Difficulty.
- Explosive Personality
As Demolitions, kill 1000 Specimens with the Pipebomb.
- Merry Men
Kill the Patriarch when everyone is ONLY using Crossbows.
- SCAR'd
Kill 1000 Specimens with the SCAR.
- Hellish Pub Crawl
Win a Long Game on West London on Hell on Earth Difficulty.
- Demonic King of the Manor
Win a Long Game on Manor on Hell on Earth Difficulty.
- Demon Farmer
Win a Long Game on Farm on Hell on Earth Difficulty.
- Boss from Hell
Win a Long Game on Offices on Hell on Earth Difficulty.
- Scientist from Hell
Win a Long Game on Biotics Lab on Hell on Earth Difficulty.
- Diablo Steel Man
Win a Long Game on Foundry on Hell on Earth Difficulty.
- Commit-ed for life
Win a Long Game on Bedlam on Hell on Earth Difficulty.
- Wolf King of the Dark Forest
Win a Long Game on Wyre on Hell on Earth Difficulty.
- Waste Disposal
Win a Long Game on Biohazard on Normal Difficulty.
- Waste Land
Win a Long Game on Biohazard on Hard Difficulty.
- Waste of Space
Win a Long Game on Biohazard on Suicidal Difficulty.
- Wasted
Win a Long Game on Biohazard on Hell on Earth Difficulty.
- Warehouse Janitor
Win a Long Game on Crash on Normal Difficulty.
- Warehouse Forklift Operator
Win a Long Game on Crash on Hard Difficulty.
- Warehouse Foreman
Win a Long Game on Crash on Suicidal Difficulty.
- Warehouse Manager
Win a Long Game on Crash on Hell on Earth Difficulty.
- Departure Gallery
Win a Long Game on Departed on Normal Difficulty.
- Departure Lounge
Win a Long Game on Departed on Hard Difficulty.
- Departure Gate
Win a Long Game on Departed on Suicidal Difficulty.
- Dear Departed
Win a Long Game on Departed on Hell on Earth Difficulty.
- Running Late
Win a Long Game on Filth's Cross on Normal Difficulty.
- Missed Connection
Win a Long Game on Filth's Cross on Hard Difficulty.
- Train Wreck
Win a Long Game on Filth's Cross on Suicidal Difficulty.
- Pile Up
Win a Long Game on Filth's Cross on Hell on Earth Difficulty.
- Gimme a Plaster!
Win a Long Game on Hospital Horrors on Normal Difficulty.
- That Bloody Well Hurts!
Win a Long Game on Hospital Horrors on Hard Difficulty.
- I'm Dying Here!
Win a Long Game on Hospital Horrors on Suicidal Difficulty.
- Not Dead Yet!
Win a Long Game on Hospital Horrors on Hell on Earth Difficulty.
- Ice Cube
Win a Long Game on Icebreaker on Normal Difficulty.
- Crushed Ice
Win a Long Game on Icebreaker on Hard Difficulty.
- Iceberg
Win a Long Game on Icebreaker on Suicidal Difficulty.
- Comet
Win a Long Game on Icebreaker on Hell on Earth Difficulty.
- Daytrip
Win a Long Game on Mountain Pass on Normal Difficulty.
- Mountaineer
Win a Long Game on Mountain Pass on Suicidal Difficulty.
- Park Ranger
Win a Long Game on Mountain Pass on Hell on Earth Difficulty.
- Neighborhood Watch
Win a Long Game on Suburbia on Normal Difficulty.
- Private Security
Win a Long Game on Suburbia on Hard Difficulty.
- Vigilante
Win a Long Game on Suburbia on Suicidal Difficulty.
- SWAT
Win a Long Game on Suburbia on Hell on Earth Difficulty.
- Slight Drip
Win a Long Game on Waterworks on Normal Difficulty.
- Burst Pipe
Win a Long Game on Waterworks on Hard Difficulty.
- Pressure Failure
Win a Long Game on Waterworks on Suicidal Difficulty.
- Floodgate to Hell
Win a Long Game on Waterworks on Hell on Earth Difficulty.
- Piece of Cake
Complete all new map achievements on Normal Difficulty.
- Pound Cake
Complete all new map achievements on Hard Difficulty.
- Fruit Cake
Complete all new map achievements on Suicidal Difficulty.
- Devil Cake
Complete all new map achievements on Hell On Earth Difficulty.
- Walking in A Winter Horror Land
Win a Long Game on Santa's Evil Lair on Normal Difficulty.
- Silent Night, Evil Night
Win a Long Game on Santa's Evil Lair on Hard Difficulty.
- I'm Dreaming of a Red Christmas
Win a Long Game on Santa's Evil Lair on Suicidal Difficulty.
- Grandma got Eaten by a Reindeer
Win a Long Game on Santa's Evil Lair on Hell on Earth Difficulty.
- Cracked the Nutcracker!
[2010 Xmas] Land the killing blow on a Christmas Fleshpound with a Knife.
- Can't Catch Me!
[2010 Xmas] Kill 2 Christmas Gorefasts with a Melee weapon from behind in one wave.
- Toasted Jack Frost
[2010 Xmas] Kill the Christmas Scrake with a Fire-based weapon.
- That's not Santa!
[2010 Xmas] Kill 3 Christmas Bloats with the Bullpup in one wave.
- Rudolph, the Bloody Nosed Reindeer
[2010 Xmas] Kill a Christmas Crawler with a Crossbow.
- Not So Silent Night
[2010 Xmas] Kill a Christmas Siren with an undetonated LAW rocket.
- Fending off Mrs. Claws
[2010 Xmas] Kill 3 Christmas Stalkers with a Lever Action Rifle without reloading.
- Tis Better to Give than to Receive
[2010 Xmas] Drop 3 Tier 3 weapons for others (with which they kill at least one Christmas Zed).
- Bad Santa
Unlock 10 of the 13 Christmas Achievements along with any Christmas Map achievement.
- Science Got Done
Win a Long Game on Aperture on Normal Difficulty.
- This is a Triumph
Win a Long Game on Aperture on Suicidal Difficulty.
- I'm Making a Note Here, Huge Success
Win a Long Game on Aperture on Hell on Earth Difficulty.
- Golden Potato
Get into GLaDOS' core on Aperture.
- Flea Circus
Win a Long Game on Abusement Park on Normal Difficulty.
- Dog and Pony Show
Win a Long Game on Abusement Park on Hard Difficulty.
- 3 Ring Circus
Win a Long Game on Abusement Park on Suicidal Difficulty.
- On Top of the Big Top
Win a Long Game on Abusement Park on Hell on Earth Difficulty.
- Lifting a Dumbell
Kill a Circus Husk with a LAW.
- Juggling Act
Drop 5 different Tier 2 weapons in one wave.
- Punk'd
Unlock 10 of the 13 Circus Achievements along with any Abusement Park achievement.
- Sparkling in the Twilight
Kill The Vampire Patriarch Ringmaster in Bedlam
- Carving The Jack O' Lantern
Decapitate a burning Halloween specimen in Bedlam
- The Scene is Zed
Kill 250 Halloween Specimens in Bedlam
- Zed October
Win a Long Bedlam Match During the Halloween Event on Hard
- This is No Ordinary Rabbit!
Kill 25 Halloween Scrakes in Bedlam
- Rule The Roost
Get all 6 achievements and unlock Commando Chicken
- Highlander
Kill a Scrake, a Fleshpound, and the Patriarch with the Claymore Sword within one map
- I love ze Healing not ze Hurting
Heal others for 3000 points of health with the MP5 SMG
- Stay Frosty
Beat Ice Cave on Hard Difficulty
- On the Rocks
Beat Ice Cave on Suicidal Difficulty
- Anti Freeze
Beat Ice Cave on Hell on Earth Difficulty
- Stuck in Limbo
Beat Hellride on Hard Difficulty
- Demonic Road
Beat Hellride on Suicidal Difficulty
- Devil's Co-pilot
Beat Hellride on Hell on Earth Difficulty
- Nail'd!
Kill 4 Stalkers in a game with the Vlad9000 Nailgun
- Second Cousins
Beat Hillbilly Horror on Hard Difficulty
- First Cousins (Once Removed)
Beat Hillbilly Horror on Suicidal Difficulty
- First Cousins
Beat Hillbilly Horror on Hell on Earth Difficulty
- Grim Reaper
Get the 6 Special Halloween Achievements plus 1 Hillbilly Horror Map Achievement to unlock the Grim Reaper
- Creepy Crawlies
Kill 15 Hillbilly Crawlers in 1 game with the Tommy Gun or MKb42
- Rippin' It Up
Kill a Hillbilly Husk and another Hillbilly Zed in the same shot with the Buzzsaw Bow or M99
- I Am Become Death
Kill 5 Hillbilly Zeds in 10 seconds with the Scythe or Axe
- Have my axe
Kill 30 Fleshpounds with the Dwarfs!? axe with back attacks
- One Small Step for Man
Kill 500 Zeds with the Schneidzekk Medic Gun while you are falling
- But It's All Red!
Collect all 16 Z.E.D. Gun pieces
- Amusing Death
Beat Moonbase on Suicidal Difficulty
- One Giant Leap (Back) for Mankind
Beat Moonbase on Hell on Earth Difficulty
- Fractional Neutron Activator
Beat Steamland on Suicidal Difficulty
- Advanced Omega Wave Resonance Explorer
Beat Steamland on Hell on Earth Difficulty
- Alpha Wave Osteooxidation Activator
Beat Steamland in Objective Mode on Suicidal Difficulty
- Tachyon Cytoneutralization Explorer
Beat Steamland in Objective Mode on Hell on Earth Difficulty
- Mrs. Punkd
Get 4 of 6 of the 2013 Summer Event in-game level Achievements, one Standard and one Objective Mode map completion Achievement, plus the Punk'd Achievement to unlock Steampunk Mrs. Foster
- Gang Crew
Beat Fright Yard on Hard Difficulty
- Stevedore
Beat Fright Yard on Suicidal Difficulty
- Wharfinger
Beat Fright Yard on Hell on Earth Difficulty
- Truck Driver
Beat Fright Yard in Objective Mode on Hard Difficulty
- Crane Operator
Beat Fright Yard in Objective Mode on Suicidal Difficulty
- Shipping Magnate
Beat Fright Yard in Objective Mode on Hell on Earth Difficulty
- Fire and Forget
Kill a Halloween Fleshpound and Scrake in the same explosion with the Seal Squeal Harpoon Bomber or the LAW
- Under The Weather
Use Bile or the Flamethrower to kill one of each Halloween Zed
- Most Bang for the Buck
Kill 10 Halloween zeds in explosions using the Seeker 6 or the M32 within 5 seconds
- King Minos
Beat Hell on Hard Difficulty
- Cerberus
Beat Hell on Suicidal Difficulty
- Lucifer
Beat Hell on Hell on Earth Difficulty
- Brain Fart
Beat Forgotten on Normal Difficulty
- Agnosia
Beat Forgotten on Hard Difficulty
- Amnesia
Beat Forgotten on Suicidal Difficulty
- Dementia
Beat Forgotten on Hell on Earth Difficulty
- Home Brewer
Beat Siren's Belch on Normal Difficulty
- Micro Brewer
Beat Siren's Belch on Hard Difficulty
- Master Brewer
Beat Siren's Belch on Suicidal Difficulty
- Trappist Monk
Beat Siren's Belch on Hell on Earth Difficulty
- Peasant
Beat Stronghold on Normal Difficulty
- Squire
Beat Stronghold on Hard Difficulty
- Prince
Beat Stronghold on Suicidal Difficulty
- King
Beat Stronghold on Hell on Earth Difficulty
- Business Class
Beat Transit on Suicidal Difficulty
- First Class
Beat Transit on Hell on Earth Difficulty
- Gone clubbing
Beat Clandestine on Normal Difficulty
- Rack 'em up
Beat Clandestine on Hard Difficulty
- Burned out
Beat Clandestine on Suicidal Difficulty
- Hangover from Hell
Beat Clandestine on Hell Difficulty
- Skull Cracker
Clandestine - Destroy 30 skulls
- Cave of Wonder
Beat ThrillsChills on Normal Difficulty
- Cavern of Pain
Beat ThrillsChills on Hard Difficulty
- Grotto of Terror
Beat ThrillsChills on Suicidal Difficulty
- Hollow of Horror
Beat ThrillsChills on Hell Difficulty
- All shook up
Destroy all (15) Snow Globes