I've noticed the G-Man walking around in various areas in HL2 and the episodes...always just outside of the normal camera range unless if you really look at him.
I realize that this is just a bit of cinematic flair and Valve is playing around here a bit, but I'm curious...is there any way to interact with him? Shoot or kill him even?
I'm currently about halfway through Episode 2 and just noticed him walking on a far-off catwalk. I didn't have access to a weapon at that point but it kind of made me wonder.