ABSTRACT:This study describes an example of design-based research in which we make theoretical improvements in our understanding, in part based on empirical work, and use these to revise our curriculum and, simultaneously, our evolving theory of the relations between contexts and disciplinary formalisms. Prior to this study, we completed a first cycle of design revisions to a game-based ecological sciences curriculum to make more apparent specific domain concepts associated with targeted learning standards. Of particular interest was using gaming principles to embed standards-based science concepts in the curricular experience without undermining the situative embodiment central to our design philosophy. In Study One reported here, the same first-cycle elementary teacher used the refined secondcycle curriculum, again with high-ability fourth graders. We then analyzed qualitative and quantitative data on student participation and performance to further refine our theory and revise the curriculum. In Study Two, another teacher implemented a further refined secondcycle curriculum with lower achieving fourth graders, including several students labeled as having special needs. We use the design trajectory and results to illustrate and warrant the creation of a situationally embodied curriculum that supports the learning of specific disciplinary formalisms.