We explore gaming with mobile flexible devices through a comprehensive study. We conducted two experiments with two commonly sized mobile devices. The first experiment created user-defined bend gestures from a set of tasks derived from gaming. The results suggest pairing opposing events by gesture location, little differences in gestures performed on two sized devices and interaction paradigms relating to the Simon Effect. The results of the first experiment were summarized and provided guidelines for the design of the game controls used in the second experiment. We implemented the user-defined gestures into 6 games using an interactive flexible prototype. Usability and user experience were evaluated and we find an overall preference for the small size, identified an important usability issue related to hand position and interaction paradigms regarding the Simon Effect and bimanual input. Finally, we propose a set of design recommendations for flexible device interactions and game designers.