Strong Closer
Take the lead 10 seconds before the end of a session and go on to win (Multiplayer Only).
6/7/2011
6:16:35 AM
Ultra Rare 4.0%
Professor Portal
After completing co-op, complete Calibration Course online with a friend who hasn’t played before
6/6/2011
8:26:05 PM
Ultra Rare 1.7%
Still Alive
Complete Course 4 with neither you nor your co-op partner dying
6/6/2011
8:00:45 PM
Ultra Rare 1.4%
Asking for Trouble
Taunt GLaDOS in front of a camera in each of the five co-op courses
6/6/2011
6:30:27 AM
Very Rare 6.0%
Obstacle Building
Complete all test chambers in the Excursion Funnels co-op course
6/5/2011
8:28:22 AM
Rare 15.7%
Bridge Building
Complete all test chambers in the Hard-Light Surfaces co-op course
6/4/2011
7:11:42 PM
Rare 20.6%
Can't Touch This
Dance in front of a turret blocked by a hard light bridge in co-op
6/3/2011
8:34:35 PM
Very Rare 7.9%
Portal Conservation Society
Complete Chamber 3 in the Hard-Light Surfaces co-op course using only 5 total portal placements
6/3/2011
7:50:27 PM
Ultra Rare 2.1%
Empty Gesture
Drop your co-op partner in goo while they are gesturing by removing the bridge under them
6/3/2011
7:14:36 PM
Ultra Rare 3.9%
Confidence Building
Complete all test chambers in the Mass and Velocity co-op course
6/3/2011
7:07:06 PM
Rare 31.6%
Iron Grip
Never lose a cube in Chamber 6 of the Mass and Velocity co-op course
6/3/2011
6:38:43 PM
Ultra Rare 2.8%
Triple Crown
Solve 3 co-op chambers in the Mass and Velocity course in under 60 seconds each
6/3/2011
6:10:53 PM
Ultra Rare 1.8%
Team Building
Complete all test chambers in the Team Building co-op course
6/3/2011
6:02:56 AM
Rare 46.8%
Four Ring Circus
Enter 4 different portals without touching the ground in co-op
6/3/2011
5:37:47 AM
Ultra Rare 4.6%
Narbacular Drop
Place a portal under your co-op partner while they are gesturing
6/3/2011
5:25:44 AM
Very Rare 5.5%
Dodge this
Achieve a kill chain of 10 or more in any Advanced Co-Op mission.
6/2/2011
6:30:37 AM
Ultra Rare 0.4%
Keep A Lid On
Complete a brawl without losing your hat as an LAPD Detective or Investigator.
6/2/2011
5:25:46 AM
Rare 48.9%