In Half-Life, the G-Man made you. In Half-Life 2, he used you to defeat Dr. Breen and start the Resistance. In Episode One, he's lost control.
I found this on the official episode 1 site. What do they mean by "the G-Man made you"?
http://ep1.half-life2.com/
also I found this
Gordon's heroics catch the attention of a sinister interdimensional bureaucrat. The G-Man, as he's come to be called, seals Gordon in stasis far from Earth, thought, and time itself.
That explains the gman!! I hope this isn't old
http://ep1.half-life2.com/story.php