https://twitter.com/majornelson
"A Dead Rising 3 demo just dropped on Xbox One. Head to the game store to download it
Or you can say “Xbox Bing - Show me game demos” and you’ll see it listed with all the game demos
The DR3 demo is in the process of rolling out. If it’s “Unavailable”- try again later. It will be available in all regions the game is sold"