The First 15 Minutes of Dead Nation (Vita)

Copied from MobyGames:Dead Nation is a top-down shooter set in a fictional environment after a zombie apocalypse. It can be played alone of cooperatively with a second player, both offline and online. Players choose between Jack McReady and Scarlett Blake. In the campaign mode a series of events gets them into contact with a Doctor Morton from the Egogate Pharmacy company who is working on a cure but needs their help.The characters can be moved around freely and they can aim in any direction. While exploring they discover chests. There is also a larger online metagame where players are grouped per country and work together to eliminate their country's infection. When complete, a new cycle starts. The money collected during missions, from chests or killing zombies, is used to buy and upgrade weapons in shops found on the maps. Zombies usually appear in large swarms and often the characters have to fight off large waves until a certain condition in the environment is met.

http://www.nicovideo.jp/watch/sm42405704