At the beginning of the game, we can see Gordon traveling in a tram to go to the huge laboratory called "Black Mesa" based in the desert of Mexico (it is the first day he works there). We are inside him, and we can watch what happens in the firm, while the tram runs.
However, we know how this strange guy named Gordon looks. He wears black glasses, he has green eyes, red hair, and a beard. We notice that we always see him with a protective suit, because he always has to survive in the game, against extraterrestrials which "accidentally" warped in Black Mesa.

He looks pretty familiar but has both a threatening and a kind look. Moreover, he never speaks, which makes him more enigmatic : we are not able to know his feelings.

Oh, I forgot to tell you his name, which is strange too. His name is Freeman. Why Freeman ? Because it is a common name ? Is it because of the adjective "free" (Gordon always has to escape aliens and Black Mesa) ?
Gordon's main enemy has a kind of link with Gordon too.
His name is G-Man, which remind us the surname Gordon. He also has a face which is nearly the same :

Translation :
Haaransatz : hair
Schädelknochen : skull
Haarwuchs : sideburns
Form und Stellung des linken Ohrs : shape and set of the left ear
Wangenknochen : the hollow of the face
Kiefer Form und Verlauf : the shape and the set of the jaw
Kinnpartie : part of the chin
NasenForm : the shape of the nose
Something is funny with his personality : he always wants to help his colleagues, but he can kill everybody, even his friends during the game (because we control him, so we can make him do stupid things), except in Half Life 2, in which he pulls down his gun when he sees friends; and if the gamer insists on killing them, they won't be hurt.
