Portal 2

Successfully complete the game.

Complete the indicated task to unlock the corresponding item for purchase at the store.

Bionic Beanie: Complete "Lunacy".
WCC Flag: Complete "High Five".

During your escape with Wheatly you will eventually run into the 'Bring your daughter to work day' room. Which has all sorts of different science fair Potato projects. If you go down to the very end of the line you will find the over grown potato. Look closely You will find the owner of the project has written her name on one of the bottom corners. Why, it's Chell!

In the first test chamber, after discovering white gel (where it comes down from a pipe infinitely), if you stay in the chamber for really long time (about 10 minutes or so), Cave Johnson will reveal secrets about Caroline and GLaDOS in a long monologue.

While attempting to earn the "Ship Overboard" achievement or trophy, once you enter the door behind the filing cabinet there are three metal doors in the hallway. If you activate the doors. Cave Johnson talks about the tests. Activate all three doors and the achievement or trophy will be unlocked.