Years ago, the Locust Horde gathered under every major city and launched a surprise attack. Untold numbers died on Emergence Day, and rather than allow the Locust to keep the spoils of their aggression, humans used chemical weapons and orbital particle beams to destroy them - and their own cities. With most urban centers and military installations rubble, survivors gathered on Jacinto Plateau, whose solid granite strata could not be easily penetrated. When the Horde breached the plateau's defenses, Marcus Fenix defied orders to save his father at East Barricade Academy - but he was too late. Charged with dereliction of duty, he has been sentenced to 40 years in Jacinto Maximum Security Penitentiary...
Not much a great game. At least is enough to have fun for a while. For being a co-op, it's not bad either, but there are not much strategies to do. In fact, in higher difficulties, most of the times you have to wait for a long time taking cover to avoid shots. Though, in some parts the real action appears and the game becomes more entertaining.
The graphics are excellent, really well worked, but the background remains similar along the game. After a while, the gameplay can get boring (I think just a few times) and also the story, that by the way I've never thought it was interesting. The game was long enough and has lots of gore, at the point I almost thought was unnecessary, but that's personal choice. And the end, though short, is the best part in my opinion. If you really games for just killing guys and with lots of blood, you won't regret playing it.