There's an integrated co-op experience where literally the two players have to work in tandem to pursue some goal. On a stealth mission, for example, you may have one guy who's moving a big, bulky shield generator unit and the other guy has to take his assault force and has to keep it underneath the cover of that shield generator unit. That's a very intimate co-op experience because they're talking into their voice-over-IP headsets and they have to coordinate their movements that way.
Red Alert 3 continues the setting of the previous Red Alert titles with an alternate history in place. With an added 3rd coalition on the rise, and the threat of mechanized ninjas - there's no way anybody should be missing this game! IGN has the full interview which is definitely worth a read.