This paper outlines two case studies of constructive design research. These describe prototypes designed to support users’ self-regulation of attention, and emotional arousal, respectively. The paper draws from key aspects of pragmatic design as well as of critical design. It also develops an argument that the described prototypes are illustrations of a critical design approach, albeit not the rather restricted conceptualization of Dunne but its revision advanced by Bardzell and Bardzell, and Senger’s reflective design