Dead Nation comes from the Dev team most famous for Super Stardust:HD which was released on the PSN in June 2007. So, here is the complete first level (16 minutes of zombie killing mayhem) for your viewing pleasure. 3 New videos have been added.
Dead Nation takes place in a fictional world afflicted by a zombie apocalypse. The player can take the role as a male or female character (in this video I've chosen the Male character) and shoot just various weapons such as Rifle, SMG, Shotgun and a Flamethrower all these weapons are upgrade-able in the weapons shop as the player processes the the level. There are many different types of zombies that have special abilities and attributes. The Player is rewarded by multipliers and money when zombies are killed, the money is used to purchase and upgrade weapons.
There's also a metagame in Dead Nation where the player is actually fighting for the country that their PSN account is logged in too, the more zombies you kill the higher up the leader board your country will go.
Multi-player can be played locally(couch co-op) or online.