Serious gaming can be used in system engineering design processes, in the pre-inception phase, where investment scenarios are explored in game sessions with stakeholders. However, scant knowledge exist in the literature about how to design this kind of games. Based on the experience of three consecutive phases of game development for infrastructure projects in biogas, local wind energy and LNG refuelling infrastructures, a generic architecture was developed and made explicit as design knowledge. This paper outlines the architecture, offers insights about its application, and explains how the validation of this knowledge takes place.