C2 is really great not only for mobile apps but also for HTML5 and desktop aps. As Silverforce said it's easy to start with C2 and there are many things to learn which let you do even pretty complex games. However it is not a pure drag&drop. You have to tell the app how it should behave in various situations, so there is a visual programming involved (based on events and actions).
Anyway there is a free version so you have nothing to loose, just take a look. Good Luck!