The Dynasty Warriors Gundam series is quite interesting. Obviously, Gundam is a nice game friendly franchise, with giant robots (not really giant robots, but still, GIANT ROBOT-LIKE SUITS, awesome) and lots of drama. Dynasty Warriors is one of the longest running co-op friendly series. The two meet and much fun can be had; I've enjoyed playing the first Dynasty Warriors Gundam over the past few weeks.
The sequel, appropriately named Dynasty Warriors Gundam 2, has just recently been released. It keeps the same solid gameplay, and adds EXTRA GIANT robots. As if that wasn't enough, three free DLC missions are coming to Xbox Live and PSN to extend the fun, each spaced out over the next few weeks. Mobile Suit Pilots, add them to your queue!