Artificial Intelligence (AI) has increasingly become a significant component of our daily routines. Therefore, it is crucial for society to familiarise young people with AI early on in their lives. We present our educational experience with the SMaILE (Simple Methods for Artificial Intelligence Learning and Education) research project. We focus on the design and development activities of SMaILE-App, a mobile game application, to teach teenagers the fundamental principles of AI. Following a constructionist pedagogical approach, SMaILE-App engages its users to learn and understand AI through suitably designed games. SMaILE-App primarily targets 12- to 18-year-old students but can also appeal to a broader audience of non-experts interested in AI technologies. Formalising the fun activities within SMaILE-App aims to facilitate a deep understanding of AI in its users. We describe SMaILE-App’s city-building game following Schell’s elemental tetrad: story, game mechanics, aesthetics, and technology.