2 things:
The antlion guard chasing after you in Ep 2
The first time in OpFor that a Gonome runs at you with its chest-teeth chomping. I didn't notice it was different from the other zombies til it was RIGHT THERE, lol
*BUMP*
I liked OpForce. It hasn't got much of a plot, but it's fun.
Blue Shift was just alright. The only interesting part IMO was fighting the marines in the trainyard. Things go crazy when you blow that hole in the wall and all the marines run up throwing SMG grenades.
Dr Rosenberg...
(This is only a joke...I think.)
Gman runs an interdimensional dogfighting ring, and Gordon's one of his prize pit bulls. (After Gordon won the fight against Nihilanth, Gman got lots of PRIZE MONNEHS)
Then in HL2 Gman won again when Gordon brought down a whole pack of Combine and their...
It wasn't Gordon's fault. He was just a "research associate" pushing carts around, not one of the ppl who designed the experiment.
He probably didn't know how risky it was.