“Evaluating Sustainability in an Imaginary World” focuses on our evaluation struggles. Despite our accidental instrumentalism (testing for how well the experience communicated obscure sustainability themes) we ended up with rich data from participants making sense of their experience largely in spite of us. That is, the aesthetically compelling qualities of SIW pushed through our inadequate framing, inspiring rich feedback on their own. In this, our larger instrumental failure yields a more important success. Art did wonderful work with participant perceptions of sustainability, just not the work we had intended. In trying to shape more appropriate evaluation strategies we examine disparities in participant reaction, wondering if our negative group might have been some of our ‘best data’ on the off chance that they were the most disrupted, and about to experience more of a transformative relationship to SIW than our more positive responders? What evaluation measures would we need to trace such possibilities? How would it need to change to understand participant experience more comprehensively? A final complication to SIW emerged in our closing discussions about ontological agency, where the more we looked at this question, the less stable it appeared. Who, or what, had ontological agency? Who or what might gain it? Was the work the ontological agent? Were the worlds inside the work? Were the participants experiencing the work? Which of these deployed the cultural intersubjectivities that constructed and constrained a thing’s being in one way or another? Which offered a reflexivity over such conditions that allowed new possibilities of being? Which gained such reflexivity and shifted possibilities of being accordingly? What, in other words, was cause and what was effect? This sudden uncertainty would prompt a very different conclusion than we had anticipated.