Go ninja go!
Digital Extremes' free-to-play shooter Warframe has done well for itself on PC and PlayStation 4. It'll probably do well on Xbox One too, which is where it's coming next, sometime this year.
Although, fact of the matter is it's not truly "free" because of that pesky Xbox Live Gold requirement, unless Microsoft waives it before Warframe releases. (Which it conceivably could and should.) This version will support second-screen functionality through SmartGlass and the Warframe Nexus App for Windows Phone, iOS, and Android.
For those of you who haven't played it but liked multiplayer in Mass Effect 3, it's worth a look. There's a nice sense of speed, and maintaining momentum by sliding is good fun.