Serious games can improve the physical rehabilitation of patients with different conditions. By monitoring exercises and offering feedback, serious games promote the correct execution of exercises outside the clinic. Nevertheless, existing serious games are limited to specific exercises, which reduces their practical impact. This paper describes the design of three exercise-agnostic games, that can be used for a multitude of rehabilitation scenarios. The developed games are displayed on a smartphone and are controlled by a wearable device, containing inertial and electromyography sensors. Results from a preliminary evaluation with 10 users are discussed, together with plans for future work.