Get the airboat's mounted gun.

Kill a Spy disguised as your current class.

Kill 10 enemies in mid-air with the minigun.

Backstab an enemy, who then switches to Pyro before they respawn.

Set five enemies on fire in 30 seconds.

Get 25 headshots as a Sniper.

Kill a burning enemy who was ignited by another Pyro.

Get five revenge kills.

Kill a gun-wielding Spy with your knife.

Backstab the enemy that you're currently disguised as.

Get a Revenge kill with a backstab.

In a single round, get a kill with 3 different weapons.

While cloaked, bump into an enemy cloaked Spy.

I'm sorry about my goat

Take 1000 points of damage in a single life.

While playing co-op, hug 3 different people on your friends list

Perform all 8 gestures of your own volition in co-op

Do the same test twice

Complete all test chambers in the Hard-Light Surfaces co-op course

Acquire the fully powered Aperture Science Handheld Portal Device.

Complete all test chambers in the Mass and Velocity co-op course

Become the Queen of Goat Ville

Knock down a turret with another turret.

This is that part

Make the correct party escort submission position decision.

Bring 8 Starites to Lily

Create an object using the Object Suggestor

That just happened

Find the hidden signal in one of the Rat Man's dens

Get the crowbar.

Hit The jackpot.

Have 10 gas cannisters explode at the same time

Get up on the skyscraper without using the elevator

Find the Sanctum 2 Walker Statue

Thrash the Goathenge

Win the title bout!

Knock a bucket into a person