- Still Alive
Complete Course 4 with neither you nor your co-op partner dying
27 March 2013 - 5 guides
- Friends List With Benefits
While playing co-op, hug 3 different people on your friends list
09 March 2013 - 4 guides
- Triple Crown
Solve 3 co-op chambers in the Mass and Velocity course in under 60 seconds each
09 March 2013 - 3 guides
- Professor Portal
After completing co-op, complete Calibration Course online with a friend who hasn’t played before
09 March 2013 - 6 guides
- Portal Conservation Society
Complete Chamber 3 in the Hard-Light Surfaces co-op course using only 5 total portal placements
08 March 2013 - 4 guides
- Iron Grip
Never lose a cube in Chamber 6 of the Mass and Velocity co-op course
07 March 2013 - 2 guides
- Asking for Trouble
Taunt GLaDOS in front of a camera in each of the five co-op courses
07 March 2013 - 3 guides
- You Saved Science
Complete all test chambers in all courses of co-op
07 March 2013 - 2 guides
- Obstacle Building
Complete all test chambers in the Excursion Funnels co-op course
- Party of Three
Find the hidden companion cube in co-op test chamber
06 March 2013 - 3 guides
- Gesticul-8
Perform all 8 gestures of your own volition in co-op
05 March 2013 - 2 guides
- Bridge Building
Complete all test chambers in the Hard-Light Surfaces co-op course
03 March 2013 - 2 guides
- Can't Touch This
Dance in front of a turret blocked by a hard light bridge in co-op
03 March 2013 - 3 guides
- Empty Gesture
Drop your co-op partner in goo while they are gesturing by removing the bridge under them
03 March 2013 - 3 guides
- Confidence Building
Complete all test chambers in the Mass and Velocity co-op course
03 March 2013 - 2 guides
- Team Building
Complete all test chambers in the Team Building co-op course
03 March 2013 - 2 guides
- Rock Portal Scissors
Win 3 co-op games of rock-paper-scissors in a row
24 February 2013 - 4 guides
- Air Show
Perform 2 aerial gestures before touching the ground in co-op
24 February 2013 - 4 guides
- Four Ring Circus
Enter 4 different portals without touching the ground in co-op
24 February 2013 - 10 guides
- Narbacular Drop
Place a portal under your co-op partner while they are gesturing
24 February 2013 - 3 guides
- Tunnel of Funnel
Master the Excursion Funnel
- Dual Pit Experiment
Do the same test twice
- The Part Where He Kills You
This is that part
- You Made Your Point
Refuse to solve the first test in Chapter 8
Unlocked offline - 7 guides
- Pit Boss
Show that pit who's boss
Unlocked offline - 6 guides
- High Five
Celebrate your cooperative calibration success
18 February 2013 - 2 guides
- Final Transmission
Find the hidden signal in one of the Rat Man's dens
17 February 2013 - 5 guides
- Lunacy
That just happened
17 February 2013 - 2 guides
- Smash TV
Break 11 test chamber monitors
17 February 2013 - 5 guides
- White Out
Complete the first Conversion Gel test
- Stranger Than Friction
Master the Propulsion Gel
- Portrait of a Lady
Find a hidden portrait
17 February 2013 - 4 guides
- Tater Tote
Carry science forward
- Ship Overboard
Discover the missing experiment
17 February 2013 - 4 guides
- Door Prize
Examine all the vitrified test chamber doors
17 February 2013 - 4 guides
- Schrodinger's Catch
Catch a blue-painted box before it touches the ground
17 February 2013 - 6 guides
- Vertically Unchallenged
Master the Repulsion Gel
- Stalemate Associate
Press the button!
- Scanned Alone
Stand in a defective turret detector
16 February 2013 - 3 guides
- No Hard Feelings
Save a turret from redemption
16 February 2013 - 5 guides
- Good Listener
Take GLaDOS' escape advice
16 February 2013 - 5 guides
- SaBOTour
Make a break for it
- Pturretdactyl
Use an Aerial Faith Plate to launch a turret
16 February 2013 - 5 guides
- Bridge Over Troubling Water
Complete the first Hard Light Bridge test
- Overclocker
Complete Test Chamber 10 in 70 seconds
16 February 2013 - 4 guides
- Preservation of Mass
Break the rules in Test Chamber 07
16 February 2013 - 3 guides
- Drop Box
Place a cube on a button without touching the cube
16 February 2013 - 5 guides
- Undiscouraged
Complete the first Thermal Discouragement Beam test
- You Monster
Reunite with GLaDOS
- Wake Up Call
Survive the manual override
16 February 2013 - 3 guides