Fistful of Brains (2008)

The town of Shadowhawk is overrun with the undead when it gets caught in the war between two brothers, each leading their own army of the undead. One of the brothers has sold the townsfolk his “magical elixir” promising them immortality. What he doesn’t tell them is that he’s recruiting them for his zombie army, and they will develop an unquenchable hunger for human flesh!