Does anyone know the game engine this game runs on? Unity? Marmalade?

I think the game is made with CocosBuilder or at least some aspects of it.
CocosBuilder is a free tool (released under MIT-licence) for rapidly developing games and apps. CocosBuilder is built for Cocos2d's Javascript bindings, which means that your code, animations, and interfaces will run unmodified on iPhone, Android and HTML 5.