You just crapped on Valves work>.>....
They didnt rig alot with zombies.They just made them use citizen animations that have almost all animations to make them be "runners".So basically most of work was from Valve:/
You go try yourself. Not as straightforward as you may think. Compiling models is the hard part everyone overlooks.
P.S Also Fifi. Black Edition Realy Isnt That Good.
Im Telling You This Now.
I Have The Game Installed But TBH It Realy Is Just Crap.
#1 Armoured Zombie ? WTF! I Got Killed Each Round By On Of Those. Overpowerd Class
We shall meet on the field of battle.