One above. One bellow. Fail.[]
Move into a space with a portal surface above and below. Now take your hands off the walking controls. Shoot an orange above you. Now a blue below you. Now realise that you just failed (no moving, that's cheating.)
Getting torn apart by Wheatly and Glados' words.[]
Press the button!
Don't you dare press that button!
Quick, press it!
I will doom you if you do!
Just press the damn button!