10 secrets GLaDOS didn't tell you in Portal 2

You solved all the normal puzzles in Portal 2, which is good for a human test subject. But you want to be great, don't you? You want to be the best tester at Aperture. You want GLaDOS to love you like your mom never did. Don't you? CVG is here to help with 10 secrets to impress in Portal 2.

This article was originally published on Joystiq.