EnderSlime

Snappy Dresser Change your costume

Portrait of a Lady Find a hidden portrait

Crush Dr. Eggman Defeat a boss for the first time.

You Made Your Point Refuse to solve the first test in Chapter 8

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

Lunacy That just happened

Pit Boss Show that pit who's boss

The Part Where He Kills You This is that part

Tunnel of Funnel Master the Excursion Funnel

Dual Pit Experiment Do the same test twice

Pturretdactyl Use an Aerial Faith Plate to launch a turret

Asking for Trouble Taunt GLaDOS in front of a camera in each of the five co-op courses

You Saved Science Complete all test chambers in all courses of co-op

White Out Complete the first Conversion Gel test

Stranger Than Friction Master the Propulsion Gel

Tater Tote Carry science forward

Ship Overboard Discover the missing experiment

Vertically Unchallenged Master the Repulsion Gel

Obstacle Building Complete all test chambers in the Excursion Funnels co-op course

Air Show Perform 2 aerial gestures before touching the ground in co-op

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

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

The Story Begins Clear SPLASH HILL ZONE, ACT 1.

Can't Touch This Dance in front of a turret blocked by a hard light bridge in co-op

Stalemate Associate Press the button!

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

Picker Onner Repeatedly pick on a player with a pie or a pilfering

Sui-Pied Pie, and eliminate, yourself from a round of Piefight

Scanned Alone Stand in a defective turret detector

No Hard Feelings Save a turret from redemption

Good Listener Take GLaDOS' escape advice

SaBOTour Make a break for it

The Cream Reaper Pie every player in the game in one round of Pie Fight

Time Bandit Score over 3200 points in one round of multiplayer Stop the Clock

Soft Boiled Achieve boiling point in a super-fast time

Hard Boiled Achieve boiling point in a fast time

Bridge Over Troubling Water Complete the first Hard-Light Surfaces test

Preservation of Mass Break the rules in Test Chamber 07

Drop Box Place a cube on a button without touching the cube

Team Building Complete all test chambers in the Team Building co-op course

Rock Portal Scissors Win 3 co-op games of rock-paper-scissors in a row

High Five Celebrate your cooperative calibration success

Undiscouraged Complete the first Thermal Discouragement Beam test

You Monster Reunite with GLaDOS

Wake Up Call Survive the manual override

Mortal Coil Shuffler Extraordinaire Accumulate 20 deaths in one Story level

Multiplier 5x Score a 5x multiplier in a Story level

Complete Da Vinci's Hideout Complete the main path of Da Vinci's Hideout