Xbox Game Preview as announced, which is their version of Early Access. It will let you follow along with development, and you can get involved today! It starts out with The Long Dark, Shelter, Elite Dangerous and DayZ. Today, only access is available for The Long Dark and Shelter, the others will be coming soon. You can go and start your free trial for the service now. You'll be able to buy and play games in development just as you can now on Steam.