Hi,
in the forums of http://www.planetwolfenstein.de someone had the idea of a Coop game mode for ET.
But I think it would be easier to do in RTCW.
His idea is to battle as one team of humans gainst AI-zombies, AI-skeletons and AI-monster.
I’ve had the idea to make something similar as “Natural Selection”.
You can join both teams.
One team are the humans.
The other team are zombies, skeletons and monster.