Play Seriously is an edited book that compiles papers from various multidisciplinary perspectives around the idea of playing, where the primary purpose is not only entertainment but also achieving educational goals. During the pandemic, video games experienced a surge in sales and usage, with an adoption of gaming habits observed not only among young people but also adults. Online platforms and multiplayer video games facilitated virtual meetings, compensating for the limitations imposed by lockdowns. Conversely, lockdown restrictions led to a significant decrease in educational and clinical interventions that traditionally required in-person interactions between users and experts. Children with special needs, in particular, faced challenges due to the weakening of connections with their therapists. From these circumstances - increased video game usage and the need for new ways to interact in educational and clinical settings - Play Seriously emerged as a CEI-Initiative funded project. It also served as a hackathon to gather for designing and creating a video game aimed at screening the early indicators of dyslexia. The book represents the culmination of a creative journey involving six universities and academies, over a hundred creators (including game designers, game artists, psychologists, pedagogists etc.), a platform (Discord) and a campus (SAE Institute of Milan), making it a truly exciting experience. Play Seriously encompasses socio-semiotic, psychological, and creative perspectives on games, guiding the reader up to the description of the practical application of the notions in a case study.