Get info from the horse’s mouth here:
http://news.xbox.com/2013/06/games-halo-spartan-assault-announcement
Epic campaign featuring 25 action packed levels with a brand new Halo story set just before the events of Halo 4.
Command many of your favorite Halo weapons, vehicles, and armor abilities, and customize your Spartan to create the perfect Spartan warrior.
Controls built for action and simplicity with virtual joysticks for touch and the added flexibility of keyboard and mouse control.
Earn XP and unlock Emblems to enhance your Spartan Career in Halo 4.
Complete weekly challenges for XP and compete against your friends in Leaderboards for ultimate bragging rights
Available for $6.99 on Windows 8 PC, tablets, and Phone. (you’ll have to buy each version separately, I believe).
PC and Tablet
Windows Phone 8 (Verizon exclusive?)