Command & Conquer Red Alert 3

The desperate leadership of a doomed Soviet Union travels back in time to change history and restore the glory of Mother Russia.

Co-op players	2
Co-op / vs-AI modes	Fully co-op campaigns (all 3 factions; online needs fan fix)
Difficulty	Easy/Normal/Hard
Price (AU)	Price n/a
Steam multiplayer tags	-
Where	Steam store page

Note: Steam doesn't tag this game "Co-op". You can still team up against the AI in skirmish.