Nsanity on 17 June 2013
There were some games that were - categorically, without a shadow of a doubt - running on Xbox One hardware. It'll come as little surprise to learn that first party software was more likely to be showcased running on the new console, with Turn 10's Forza Motorsport 5 the most high profile title we saw that was visibly operating on the actual console.
http://www.eurogamer.net/articles/digitalfoundry-hands-on-with-xbox-one
