ArabianSwordsman

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

Empty Gesture Drop your co-op partner in goo while they are gesturing by removing the bridge under them

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

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

Pit Master Discover and fight Hidden Kombatant 3 in Arcade Ladder

Arcade Champion Complete Arcade Ladder with All Fighters

The Competitor Complete 200 Versus matches (online OR offline)

Wild, Man! Complete the "Base Camp" campaign.

The Krypt Keeper Unlock 100% of the Krypt

Undertaker Unlock 50% of the Krypt

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

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

Best...Alternate...Ever! Unlock Mileena's 3rd Alternate Costume

Tower Master Complete all Tower missions

I "Might" Be the Strongest Complete all Test Your Might mini-game challenges

These Aren't My Glasses! Complete all Test Your Sight mini-game challenges

Dim Mak! Complete all Test Your Strike mini-game challenges

Ladder Master Complete Arcade Ladder on max difficulty without using a continue

White Out Complete the first Conversion Gel test

Stranger Than Friction Master the Propulsion Gel

Hide and Seek Discover and fight Hidden Kombatant 2 in Arcade Ladder

Brotherhood of Shadow Discover and fight Hidden Kombatant 4 in Arcade Ladder

Ultimate Humiliation Perform every fighter's hidden finishing move

e-X-cellent! Successfully land every playable fighter's X-Ray

The Grappler Perform every fighter's forward and backwards throws

Finish What You Start! Perform a Fatality with all playable fighters

Tater Tote Carry science forward

Vertically Unchallenged Master the Repulsion Gel

Stalemate Associate Press the button!

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

Pturretdactyl Use an Aerial Faith Plate to launch a turret

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

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

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

Undiscouraged Complete the first Thermal Discouragement Beam test

You Monster Reunite with GLaDOS

High Five Celebrate your cooperative calibration success

Wake Up Call Survive the manual override

You've Got Style! Unlock all Alternate Costumes

What Does This Button Do?? Complete Arcade Ladder without blocking (allowed to continue)

Robots Rule! Win Arcade Tag Ladder with robot Sektor and Cyrax

Quan-Tease Unlock Hidden Fighter "Quan Chi"