This paper uses a series of serious games - a form of participatory modelling designed and played in Kandal, Cambodia -as an entry point for reexamining relations between development projects, participatory formats, landscape transformations, and sustainable futures. Critics of development and participation have shown that participatory formats simplify real-world complexities by rendering them technical. This is also the case for serious games. But contrary to what is often assumed, 'depoliticization' is not the unavoidable outcome. Instead, participatory outcomes depend on specific sociotechnical patterns of more or less generous constraints. To support collective exploration requires tinkering with these patterns of constraints to keep the boundaries between virtual and real worlds, insiders and outsiders, and the present and future relatively permeable. Generous constraints and permeable boundaries do not keep power out of participation but facilitate glimpses of different possibilities. In Kandal, they made it possible to shift from narrow technical discussions on the rehabilitation of specific preks (water channels) towards a collective exploration of sustainable futures for the full mosaic landscape. In general, we argue, serious games hold potentials as experimental systems, which are serious to the extent that they work like technologies of humility. In this capacity, they can support efforts to do difference together, and explore more-than-human worlds and divergent practical ontologies. Learning from this multiplicity matters for moving towards sustainable forms of living in Kandal and elsewhere.