The X1 Backwards Compatibility is now live for Xbox Preview Members. If you have any digital Xbox 360 games that is on the list you can download them now or if you own the disc based game load it up on your Xbox One. To download Digital Based games go to your Games and Apps tab and scroll all the way to the right where you see Ready to Install games.
For a list of the current games available go check out this: https://www.horizonmb.com/threads/173300-List-of-Backwards-Compatible-X360-Games
Q: How do I get to the Xbox 360 Guide on my Xbox One?
A: While playing your Xbox 360 game on Xbox One, you can access the Xbox 360 Guide by pressing the Menu and View buttons on your Xbox One controller at the same time. (Note: some games have additional functionality when pressing either the Menu or the View button individually. Be mindful there may be unexpected behavior if you press one button prior to the other. Check the Game Specific Issues in the Known Issues for workarounds in specific titles.)
Q: Can I continue a game that I started on my Xbox 360?
A: If you have saved your games to the cloud from an Xbox 360, you will be able to continue that game on the Xbox One. Some titles do not support cloud storage. In those cases, game saves will not be recovered on the Xbox One. Please refer to the list below to see which titles do not support cloud storage. For help on saving your games to the cloud from your Xbox 360 console, check the following articles:
Setting up cloud storage on 360: http://support.xbox.com/en-US/xbox-360/games/cloud-save-games
Q: I saved my game on Xbox One but don’t see the saved game on my Xbox 360. What happened to my game?
A: Xbox 360 game saves are uploaded after you quit the game on Xbox One. You must quit it from Home or launch another non-backward compatible game in order for the save to be uploaded. If you turn off your console, it will be uploaded when you turn it back on.
Q: Can I play multiplayer with friends who are playing the game on Xbox 360 or Xbox One?
A: Yes! For games that have multiplayer, you will be able to play with others who own the title on Xbox 360. For Xbox One users, only members of the Public Preview audience who own the game will be able to play with you during this beta.
Q: Will I need to earn my game achievements again on the Xbox One?
A: No, if you originally earned the game achievement on the Xbox 360 you will not get duplicate achievements nor lose your previous achievements.