It was easy for me.
Two Words:
Invincibility Cheat
(I have the Xbox360 version of Orange Box. Invincibility cheat on all games on it except TF2! Yes, even portal.)
I once saw in a Youtube video a guy who noclipped or something to a island with the 2 advisors that pop up in the end of ep 2, but they didn't move or anything. Just ragdolls frozen in mid-air. But, you can shoot them, whack them, do anything to hurt them and hit marks will show up.
Yes, in the...