Yipes, I didn't realise ( or maybe I've forgotten ) that Freespace 2 has co-op. Now I definately need to get my brothers to buy a copy so we can purge the universe of evil-doers and good-doers alike
But i forget to mention that co-op in Freespace 2 is only in missions not campaign. Still some missions are connected or there is a series of missions in co-op multi Freespace 2.
Also Sacred Gold
I forget - Obscure
of course! Its the only survival horror with cooperation mode. But watch out! Its very console like coop - one player is using game pad or right side of the keyboard and second one is using left side of the keyboard (or game pad :P ) So its kind of not multi coop.