This chapter explores how Tabletop Role-Playing Games (TTRPGs) can act as social laboratories for sustainability education. Through structured yet emergent play, they enable players to engage with governance models, resource distribution, and ethical dilemmas. The findings aim to inform future approaches to games engineering and pedagogical innovations for sustainability education. It draws on gameplay analysis as a methodological approach, based on data from two case studies: Empaville (4 playtests, totalling 360 minutes of gameplay) and a modified version of Dungeons & Dragons (4 one-shot sessions, totalling 16 hours). Using the Activity Theory-Based Model for Serious Games (ATMSG), these studies consider how game mechanics, instructional scaffolding, and social interaction shape learning. Findings show that TTRPGs are not just storytelling platforms but spaces for problem definition, civic imagination, and systems thinking. The study highlights the porous nature of the Magic Circle, where boundary objects, immersive storytelling, and emotional bleed blur distinctions between play and reality, influencing decision-making and engagement. These insights challenge traditional models of serious game design, which often prioritise fixed learning objectives and reward systems, instead advocating for a relational and emergent approach to game-based pedagogy. By cultivating narrative agency, adaptive thinking, and emotional engagement, TTRPGs provide a transformative model for engineering educational games for a sustainable society, preparing players to navigate the uncertain, complex, and ethical trade-offs of real-world problems.