Vanilla Crazy Cake
Beat all advanced chambers
35 
Fruitcake
Beat 10 advanced chambers
25 
Out of the Blue
Once you have control of both portals, only enter the orange portal.
25 
Is Anyone There?
Complete the game without ever taking a bullet.
20 
Like a Rat
Trap yourself in a test chamber so that GLaDOS has to help you continue.
20 
Go for the Gold
Win a gold medal on a challenge map.
15 
Rat's Tale
Find all the Rat Man dens.
15 
Tests Like Chicken
Find the chicken's test results.
15 
Cupcake
Beat 5 advanced chambers
10 
The Camera Adds 10 Pounds
Knock a turret over with a security camera.
10 
Saw That One Coming
Cause a rocket sentry to destroy its own rocket when the rocket has been redirected back towards it.
5 
A Feeling Like Floating
Dissolve a turret.
5