What does it mean to build digital worlds in the Anthropocene? Despite their compromised provenance, computer and video games offer a potent avenue for designing and partaking in environmental scenarios. As a review of the varied approaches to ludic world design suggests, differences in opinion as to who or what constitutes a viable game world – broadly speaking, designers, players, software or spaces – bear on environmental impasses in our shared world, which is marked by multispecies entanglements and obligations. If the essence of world-building lies primarily not in a singular, authorial intent or vision but in a collective imagining and realisation, then designed worlds may serve as both inspirations and cautionary tales for our ecologically compromised times.