He's a Hazard Course professional. Knows his way around shafts and trains, that stuff n' fluff enough. But I suppose you can always chalk it up to FPS main character syndrome and the power of a silent shotgun-wielding warrior. This naturally explains the other one-man-army case of Barney Calhoun, who took down a tank and a whole squadron of grunts at the same time all by himself.

Some people also think that the save/load feature is Gman making sure Gordon always comes out on top in some sort of meta-fourth-wallerly-way. Others chalk it up to the magical properties of the HEV suit and obscene amounts of morphine.

But what you should really be wondering is how the guy can see his health and armor at all times. Must be one high-end top-of-the-industry pair of indestructible and comfort-built glasses.