The increasing ‘digitalisation’ of society presents a double-edged sword for transitioning towards an environmentally sustainable future. Our everyday interactions with product-service-systems, like ‘smart’ Internet of Things (IoT) devices, Artificial Intelligence-driven (AI) interfaces, and Massively Multiplayer Online games can help to make our lives more connected, convenient, and convivial. Due to their perceived immateriality, these systemic technologies are often also promoted as resource efficient and sustainable. Yet, because of their ubiquity and scale, these innovations are consuming precious planetary resources at an alarming rate. With a global footprint of 4% of carbon emissions and counting, digital technologies help to increase the Earth’s temperature and contribute to climate change, creating risks for biodiversity and human life. This chapter presents three case studies that, through the design and deployment of novel, interactive Serious Games, creatively interrogate the unsustainability of today’s socio-technical eco-system. Like Games for Change and Persuasive Games, Serious Games aim to provide more than simply an entertaining experience for players. They can help to raise peoples’ awareness and understanding of complex, real-world systemic issues including poverty, geo-political conflict, and climate change. Drawing upon insights generated through Participatory Speculative Design workshops alongside Bogost’s notion of Alien Phenomenology, the cases outline how Research through Design and Worldbuilding methods were applied to create the three More-than-Human game experiences. This emergent approach to More-than-Human-Centred Design allows practitioners to concretise and consider the tensions and trade-offs that exist between human and non-human actants including ecological stakeholders (e.g., flora, fauna, climate) and technological counterparts (e.g., data, AI, devices) across our contemporary socio-technical eco-system.