Stroke is affecting different age groups worldwide with tremendous consequences. Most stroke survivors suffer from motor impairment, where rehabilitation helps to regain lost abilities. Rehabilitation is a long process that focuses on repeating exercises, which are monotonous and time consuming. As a consequence, patients loose interest and motivation. Serious games offer the possibility to deliver rehabilitation exercises in combination with entertaining and motivating aspects. A variety of serious games using additional hardware is available to support stroke patients. In this article, the authors propose a new and innovative serious game, which relies only on integrated sensors of a smartphone. Development was based on a user-centered design approach divided into two phases. In phase 1, requirements were identified in cooperation with a therapist and 13 stroke patients. The developed serious game included different levels of difficulty for movement, gesture, and touch exercises. Additional feedback and requirements from therapists and medical doctors were included in phase 2, which resulted in an advanced solution with additional levels. Gathered feedback showed a positive attitude toward the proposed solution.