Virtual reality (VR) has gained traction in rehabilitation by enhancing patient engagement and adherence to physical therapy. Traditional rehabilitation methods often suffer from monotony, leading to lower compliance. RhythMotion, a VR rhythm-based game, integrates therapeutic exercises with music-driven gameplay to improve upper-body mobility. The game features two stages: Stargazing, which targets neck movements, and Stellar Stretch, which focuses on arm exercises. A user study involving physical therapy specialists, former patients, and general participants showed high engagement and perceived practicality for rehabilitation. Participants found RhythMotion enjoyable and motivating, with specialists recognizing its potential in home-based therapy. Feedback suggested improvements in calibration, motion tracking, and onboarding instructions. Overall, this study highlights the potential of VR-based rehabilitation in fostering adherence and making therapy more interactive and enjoyable.