The potential of games in empowering underrepresented groups is a central theme in the field of media studies. However, to ensure that everyone can benefit from them, it is necessary to ensure that they are inclusive and accessible. In the present work, we have implemented a Participatory Action Research (PAR) approach to target this problem, right at the stage of training new game designers and game developers. Thus, through a game-design-based or experimental game design pedagogical approach, we intended to promote inclusive and accessibility-driven game design and development skills in students, while decreasing their negative attitudes towards people with Intellectual Disability (pwID). A protocol with a Non-Governmental Organization in the field was established and, during two semesters, students were challenged to develop 10 accessible games and physical interfaces for pwID and motor disabilities, through participatory processes. Pre and post assessment was conducted, through a mixed-method approach. After participating in this process, students reported satisfaction and increased knowledge of cognitive and motor accessibility, and inclusive game design in general. Moreover, the attitudinal assessment showed significantly lower levels of prejudiced beliefs towards pwID (p < 0.05).