One of the short stories from the "Raising the Bar" book called "Now Arriving: City 17" had a sentence that might give us an idea to who/what the gman is. The sentence was something like "a face plagued by erratic tics(involuntary muscle movements) that suggested extreme senility or neural damage...". So, this might mean a) Gman has made himself somehow immortal (he looks the same, but his mind is decaying). b) Maybe during the Black Mesa incident he endured some head trauma, and is now some time-hopping pyscho.
Oh, and did anyone else notice that when the gman talks to you at the end of both HL games, it happens right near a teleporter?. The Citadel had one, and after you destroyed Nihilanth, the screen was going white and it seemed you were going to be teleported somewhere else. Then the gman stepped in and saved you.
Oh, and did anyone else notice that when the gman talks to you at the end of both HL games, it happens right near a teleporter?. The Citadel had one, and after you destroyed Nihilanth, the screen was going white and it seemed you were going to be teleported somewhere else. Then the gman stepped in and saved you.