Break your CPU.

Kill five barnacles with one barrel.

Escape the apartment block raid.

please don't touch anything

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

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

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

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

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

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

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

Complete Portal.

Do whatever it takes to survive.

Examine all the vitrified test chamber doors

Complete Test Chamber 10 in 70 seconds

24 hours of your life wasted

Eat 200 balls

Experience 500 Lua programming errors

Master the Excursion Funnel

Complete the first Conversion Gel test

Master the Repulsion Gel

Break the rules in Test Chamber 07

Making Friends

Recruit an Operative in Campaign Mode after completing 'Reporting For Duty'

Play 20 different maps

Big Bully

Knock someone over

One small trip

Qualify from your first round