Exercise gaming has been receiving a significant interest from both consumers and researchers. Be it for the purposes of weight loss, physical fitness or even just enjoyment, the potential of games to support rehabilitation has also been under investigation for a while. Due to our aging society, game based therapies could be a solution for optimizing resources and reducing rehabilitation costs. This paper aims to discuss the potential capacity of games as systems to enhance the relation of physical exercise and cognition for the rehabilitation of Parkinson Disease. Our investigation demonstrates that there is no established methodology for games in rehabilitation of Parkinson's addressing how games can encapsulate physical exercise strategies while providing safety, continuous monitoring and cognitive development exercises in facilitation of rehabilitation. Since rehabilitation with games is trending, yet to be developed rehabilitation strategies would benefit from new insights into the relationship between game worlds, physical exercise and motor-cognitive training. Therefore, it is useful to do further research into realizing (1) a relational model that demonstrates the relation between game world (composed of game features including formal game elements, audio-visual features, mechanics and dynamics), motor skills, cognition and physical exercise for both generic and specific rehabilitation purposes, (2) a structured task creation approach for game features that reconciles specific rehabilitation outcomes, correct level of engagement, task difficulty and safety requirements for target demographic.