Several studies have shown that game-based rehabilitation is a viable option to improve the treatment of patients with physical disabilities. Even though many games are built focusing on rehabilitation, the majority does not present a broad study about the right approach on the many types of existing conditions and also the physiological and medical implications of this games in the patient's treatments. The actual level of integration between Unity and the body-tracking device supported by Microsoft Kinect, has provided a solid tool to build a serious game focusing the rehabilitation paradigm. This work presents the steps and foundation regarding the subject to build a serious game with focus in rehabilitation of the upper limb, more specifically of those patients with hemiplegia or hemiparesis, with the use of biofeedback analysis to evaluate the patient's development. It also shows the possibility of the multiplayer perspective into the rehabilitation treatment to help with the learning phase and bring motivation to the gaming experience.