On the lvl Water Hazard, before u break through the wood zoom and look at the building. Gman will be standing near the railing. check it out
EDIT: I beat the game 2 times and never noticed!
He is scattered throughout the game in places you wouldnt expect to find him. I dont remember all of them cause i havent played sp in a while, but im pretty sure hes on a platform near the end of the game when your riding in those pod thingys. Someone actually had a screenshot of every part he was in, but i cant find it.
And near him, there is a man with his FACE EATEN AND BURNT OFF!
Jakkc... Anyway Sumiriku a Print Screen would be nice!
Alright ill do that
Here it is with all of the other Gman sightings...Youll be able to tell which one i was talking about. It looked exactly the same as if i were taking a screenie. http://www.hlfallout.net/articles.php/44/3/