After completing co-op, complete Calibration Course online with a friend who hasn’t played before

Unlocked: 17 Jul 2011 13:11:54

Complete Course 4 with neither you nor your co-op partner dying

Unlocked: 05 Jun 2011 18:26:33

Complete all test chambers in all courses of co-op

Unlocked: 05 Jun 2011 01:16:28

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

Unlocked: 05 Jun 2011 00:11:27

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

Unlocked: 04 Jun 2011 22:03:47

Complete Chamber 3 in the Hard-Light Surfaces co-op course using only 5 total portal placements

Unlocked: 04 Jun 2011 21:44:11

Solve 3 co-op chambers in the Mass and Velocity course in under 60 seconds each

Unlocked: 04 Jun 2011 21:18:07

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

Unlocked: 04 Jun 2011 17:19:49

Find the hidden companion cube in co-op test chamber

Unlocked: 04 Jun 2011 17:17:30

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

Unlocked: 04 Jun 2011 16:43:17

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

Unlocked: 04 Jun 2011 16:26:08

Dance in front of a turret blocked by a hard light bridge in co-op

Unlocked: 04 Jun 2011 15:52:29

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

Unlocked: 04 Jun 2011 14:58:45

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

Unlocked: 04 Jun 2011 14:54:29

Place a portal under your co-op partner while they are gesturing

Unlocked: 04 Jun 2011 14:52:28

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

Unlocked: 04 Jun 2011 14:51:50

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

Unlocked: 13 May 2011 13:25:33

Never lose a cube in Chamber 6 of the Mass and Velocity co-op course

Unlocked: 13 May 2011 13:14:54

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

Unlocked: 13 May 2011 12:56:02

Enter 4 different portals without touching the ground in co-op

Unlocked: 13 May 2011 12:35:12

Celebrate your cooperative calibration success

Unlocked: 13 May 2011 12:13:13

Break 11 test chamber monitors

Unlocked: 06 May 2011 11:37:55

Examine all the vitrified test chamber doors

Unlocked: 05 May 2011 22:00:31

Find a hidden portrait

Unlocked: 05 May 2011 21:42:24

Take GLaDOS' escape advice

Unlocked: 05 May 2011 21:37:58

Break the rules in Test Chamber 07

Unlocked: 05 May 2011 21:17:11

Use an Aerial Faith Plate to launch a turret

Unlocked: 05 May 2011 21:14:12

Show that pit who's boss

Unlocked: 05 May 2011 21:01:28

Complete Test Chamber 10 in 70 seconds

Unlocked: 05 May 2011 20:58:12

That just happened

Unlocked: 05 May 2011 20:34:20

This is that part

Unlocked: 05 May 2011 19:54:19

Master the Excursion Funnel

Unlocked: 05 May 2011 18:58:47

Do the same test twice

Unlocked: 05 May 2011 17:58:12

Refuse to solve the first test in Chapter 8

Unlocked: 05 May 2011 17:56:58

Complete the first Conversion Gel test

Unlocked: 05 May 2011 17:18:05

Master the Propulsion Gel

Unlocked: 05 May 2011 16:06:24

Discover the missing experiment

Unlocked: 05 May 2011 10:37:39

Carry science forward

Unlocked: 05 May 2011 10:34:03

Catch a blue-painted box before it touches the ground

Unlocked: 04 May 2011 22:10:52

Master the Repulsion Gel

Unlocked: 04 May 2011 21:49:14

Press the button!

Unlocked: 04 May 2011 20:51:34

Stand in a defective turret detector

Unlocked: 04 May 2011 20:33:10

Save a turret from redemption

Unlocked: 04 May 2011 20:29:16

Make a break for it

Unlocked: 04 May 2011 20:17:01

Complete the first Hard Light Bridge test

Unlocked: 04 May 2011 19:18:35

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

Unlocked: 04 May 2011 18:52:36

Place a cube on a button without touching the cube

Unlocked: 04 May 2011 18:46:21

Complete the first Thermal Discouragement Beam test

Unlocked: 04 May 2011 18:31:49

Reunite with GLaDOS

Unlocked: 04 May 2011 18:27:29

Survive the manual override

Unlocked: 04 May 2011 18:03:15