Horizon: Zero Dawn looks pretty cool!
Concept looks pretty cool. I just hope Guerilla Games has hired someone better for their story, because Killzone's biggest failure has always been its plot.
Guerilla Games has historically had amazing visual designs and atmosphere/premise, but their stories have always left a lot to be desired.
[UPDATE]: The XBox 360 backwards compatibility is essentially an XBox 360 emulator (probably an app) that will play those games as they are enabled over time. It will allow only 360 achievements to be saved, but essentially everything from the 360 - friends, achievements, chat, etc. - will be accessible, though no real details on whether previously downloaded GwG will carry over. So basically, a virtual 360 on your XBox One that can use XBox One features.
It sounds like the games - owned or not - will need to be downloaded onto the XBox One HDD to be played, but inserting a 360 disk will be recognised if the game is in their catalogue and will be free. The emulator won't accept USB peripherals (arcade sticks are a no-go, I presume

), and the original Kinect isn't compatible, but the catalogue will be gradually expanded, and
"really the only thing that stops us is getting the legal permissions for stuff like licenses that may have changed over time or whatever the case may be".
Most of the first-party lineup will be enabled first, followed by feedback from sources such as voting systems, fan favourites, popular games still played on the 360, etc.
> Taken from an XBox preview video with Larry Hryb (Major Nelson) and Bill Stillwell (XBox Platform Team).
Since I didn't own a 360 at the time of its ongoing compatibility releases, I don't know if this is what they said they'd do before, but they'll want to do a good job on this if they want to remain in the good graces of the public and generate more XBox One sales.
[UPDATE UPDATE]: Felt like this is partially relevant: