Here is a short videos of some apps in the Windows Store that use Cocos2D-x.
Cocos2D-X is an open source C++ game engine aiming at extending the reach of the popular Cocos2D game engine to other OS platforms beyond iPhone. Cocos2D-X is used by many mobile gaming creators, from hobbyists to major publishers like Zynga, Konami, Glu, Gamevil and KingSoft.
Microsoft Open Technologies contributes to the Cocos2D-x project to bring and maintain the support for Windows Store and Windows Phone.
To learn more, visit http://aka.ms/cocos2d-xonwindowsdevices