Shephard has a cool gas mask and more weapons than Gordon. One of Shephard's weapons is his pet, how cool is that?

Shephard is so badass, he took on the entire Black Ops and wiped the floor with them. Meanwhile Gordon was so scared of the Black Ops that he decided to only fight the women (damn that's low bro).

He also wears a helmet, Gordon doesn't cause he's stupid.

Valve will never bring back Shephard cause they know he'll overshadow the orange nerd. That makes them seethe hard. Marc Laidlaw proably got so envious of the writers at Gearbox that he decided to never mention Chad Shephard or any of the creatures from OF in any of the HL sequels.

Gaben got so angry that he started pissing and ♥♥♥♥♥♥♥♥ himself on a daily basis, the stress of not being able to live up to Shephard and Opposing Force made his hair go gray. The realization that nothing they make will ever surpass Shephard is what made them abandon HL3.