http://www.ign.com/articles/2013/10/18/zoo-tycoon-for-xbox-one-is-a-timed-retailer-exclusive

IGN has confirmed with Microsoft that upcoming Xbox One launch title Zoo Tycoon will only be available in retail at Walmart for a limited time. It will, however, still be available as a digital download from the Xbox Games Store.

"Zoo Tycoon for Xbox One will be exclusively available at Walmart in the U.S. between November 22, 2013 and January 31, 2014," the company told us. "Customers can also purchase Zoo Tycoon for Xbox One at Microsoft Stores and download the title on Xbox Live."

The game is also shipping for current-gen, though the Xbox 360 version is not exclusive to any retailer. "Zoo Tycoon for Xbox 360 will be available at all major retailers," Microsoft clarified.