Without a doubt, of E3 2015's biggest surprises (opens in new tab) was the support of Xbox 360 games with a new Xbox One backwards compatibility (opens in new tab) feature. The program is currently available only for Xbox One Preview Program members (basically a fancy way of phrasing "beta") but thanks to Xbox Support and Xbox spokesman Larry "Major Nelson" Hryb, we now have some more details on what the feature will include when it goes live for all Xbox One owners. Chief among these details: DLC, Achievement, cloud save and multiplayer support.
When asked on Twitter if DLC would carry over to Xbox One, Xbox Support responded (opens in new tab) that the console itself will not prevent such action, but that "DLC of specific titles is up to the publisher." Hryb also confirmed via a video (embedded below) that Achievements, cloud saves and even multiplayer would still function just as they did on Xbox 360 - provided that the servers are still up, of course. Backwards compatibility may be a powerful weapon in Xbox's pocket, but even it has limits.