I dig the animated style of the trailer, along with the extra creepy version of a holiday classic song. From the Official Website:

It’s the holiday season in Willamette, Colorado and a mysterious outbreak has overrun the Willamette Memorial Megaplex Mall and surrounding town with dangerous and deadly predators. Join Frank West as you explore a vast, open world sandbox filled with dangerous new zombies and a million ways to kill them as you seek to uncover the truth behind the outbreak – or die trying.