It came from space, and ate our brains

Brainless

Common57.4%

Die for the first time

Got Your Back

Uncommon39.2%

Kill an enemy close to a player with one health

Medic!

Uncommon34.2%

Complete Hospital on any difficulty

Wipeout

Uncommon31.1%

Kill 1,000 aliens

No-Brainer

Uncommon30.2%

Reach 50x multiplier

Because 1337 Is Too Mainstream

Uncommon23.1%

Kill 1338 Pink Crawlers

Ignored The Signals

Uncommon22.4%

Complete City on any difficulty

Rain Of Bullets

Uncommon21.8%

Buy all Machine Gun upgrades in one game

Last Man Standing

Uncommon20.3%

Stay alive while other players are waiting to respawn

Pistolero

Uncommon19.3%

Buy all Pistol upgrades in one game

Hold The Line

Uncommon16.2%

Place 50 Turrets

Facemelter

Uncommon16.1%

Buy all Plasma Gun upgrades in one game

Science!

Uncommon15.7%

Buy all Laser Gun upgrades in one game

In The Spotlights

Uncommon15.3%

Use Beams 50 times

Loving My Bubble

Uncommon15.3%

Use the Shield 50 times

Tread Carefully

Uncommon14.6%

Place 150 Mines

This was a triumph

Uncommon14.6%

Finish a multiplayer level and win it.

My Way Or The Highway

Uncommon14.4%

Complete Highway on any difficulty

Hoarder

Uncommon13.9%

Collect 250 pick-ups

All Together Now

Uncommon12.7%

Reach 100x multiplier

Most Valuable Player

Uncommon11.8%

Get the highest score in a co-op multiplayer game

Hunting Season

Uncommon11.0%

Buy all Shotgun upgrades in one game

Smelled The Fresh Air

Uncommon10.4%

Complete Countryside on any difficulty

Taken

Rare8.4%

Complete Crash Site on any difficulty

In The Navy

Rare8.0%

Complete Navy on any difficulty

C-c-c-combo!

Rare7.4%

Reach 150x multiplier

Go Go Gadget

Rare7.2%

Pick up 50 weapon upgrades dropped by the S.W.A.T. Drone.

Had A Blast

Rare6.7%

Buy all Rocket Launcher upgrades in one game

Space Janitor

Rare6.5%

Kill 10,000 aliens

Heavy Metal

Rare5.8%

Complete Industrial on any difficulty

It Came From Earth...

Rare5.4%

Complete Planet on any difficulty

Home Sweet Home

Very rare4.8%

Complete Suburbs on any difficulty

Scrapyard Challenged

Very rare4.1%

Complete Scrapyard on any difficulty

Houston...

Very rare3.8%

Complete Launch Pad on any difficulty

Randomized

Very rare3.6%

Shoot 95471 times

Unsinkable

Very rare3.4%

Complete Ship on any difficulty

Jerrycan

Very rare2.9%

Complete all Survival levels on Medium

They Walked Into My Gun

Very rare2.8%

Complete all Survival levels on Easy

Unmissable

Very rare2.1%

Get the highest score in a co-op multiplayer game ten times

Saving The Day

Very rare1.6%

Revive 50 people using Medkits

Not Giving In

Very rare1.4%

Complete a co-op multiplayer game on Insane without dying

Hardened

Very rare1.3%

Complete all Survival levels on Hard

Insane In The Membrain

Very rare1.3%

Complete all Survival levels on Insane

Scrooge

Very rare1.3%

Collect 25,000,000 coins in total (accumulative)

Semi-Pro Alienator

Very rare1.3%

Complete three co-op multiplayer games on Insane without dying

Brainfest Has Been Cancelled

Very rare1.2%

Complete six co-op multiplayer games on Insane without dying

On Top Of The World

Very rare1.2%

Complete Rooftops (Campaign) on any difficulty

Total Annihilation

Very rare1.2%

Kill 100,000 aliens

Perioperative Mortality

Ultra rare0.7%

Complete Clinic (Campaign) on any difficulty

Not Hogan's

Ultra rare0.5%

Complete Alleys (Campaign) on any difficulty

Tunnel Vision

Ultra rare0.3%

Complete Sewers (Campaign) on any difficulty

Winter Is Coming

Ultra rare0.3%

Complete Riverside (Campaign) on any difficulty

Caved In

Ultra rare0.2%

Complete Cave (Campaign) on any difficulty

Wave Your Hands In The Air

Ultra rare0.2%

Complete all Campaign levels on Easy

Can't Touch This

Ultra rare0.1%

Complete all Campaign levels on Insane

Stop... Hammer Time!

Ultra rare0.1%

Complete all Campaign levels on Hard

Why Would I Ever Stop Doing This?

Ultra rare0.1%

Complete all Campaign levels on Medium