Applying innovations in digital health technologies, such as exergames, has been recommended by official bodies like the World Health Organization for health promotion and disease prevention across various populations and age groups. Given a key advantage of interactive and gamified digital health technologies is promoting user engagement, a substantial proportion of studies have implemented recreational exergames - games primarily designed to make specific activities more fun and entertaining. In this article, we aim to move beyond the benefits of "just" providing a more engaging environment for physical and motor-cognitive activities/exercises by shedding light on serious exergame features that enhance the ecological validity of exercises and offer unique advantages for tailoring interventions beyond conventional approaches. To this end, we review the roles and mechanisms of specific exergame features in supporting adherence to relevant behavior change, neuroscience, and exercise science principles, and integrate our findings into the ‘Beyond “Just” Fun of Exergames Framework’. This framework (i) implements a definition and classification approach to harmonize and provide more nuanced terminology for specific application scenarios of exergame technologies, and (ii) delineates best practices for the theoretically grounded selection and implementation of exergame features in health promotion and primary through tertiary disease prevention (including rehabilitation). By introducing this framework, we aim to support a paradigm shift by guiding game designers, researchers, and exercise and therapy practitioners from entertainment-centered recreational solutions towards serious exergames that are purposefully designed with adequate theoretical underpinnings, thereby unlocking the full potential of exergame-enhanced interventions for individuals and public health needs.