A lot of information came out just recently about the Resistance 2 co-op gameplay. It has been known for a long time that the co-op can cater for up to 8 players and that the levels would be different from the single player campaign. However, it is slightly different from what I imagined it was going to be.
I thought the co-op would be you and a group of friends playing through most of the campaign the same as in single player but with new levels and some alterations to other levels to make them more suited to co-op gameplay. I read
THIS article on Kotaku yesterday that explains it differently. It seems like you get a squad together and make your way across maps, achieving objectives all the while fighting off hordes of enemies. It doesn't sound like there is a story attached to this mode.
I suppose I am a little disappointed with the news but they do make this mode sound like fun. Plus it is always good to have different modes in games to ensure longevity of a title.