Conducting an iterative usability testing, a set of prompts used as a form of instructional support was developed in order to facilitate the comprehension of the diffusion of innovations theory (Rogers, 2003) in a simulation game called the Diffusion Simulation Game (DSG) (Molenda & Rice, 1979). The six subjects who participated in the study stated that the prompts were necessary in order to properly complete the game and that they would have done worse without them. However, the game performance and learning test scores did not correspond to the notion that the prompts significantly enhanced the learners' performances in the DSG or increased their knowledge of the underlying game theory. We assume that, as the DSG is a complex strategy game, the prompts may not be sufficient support by which to help learners. As such, it is possible that the game requires a different type of instructional support. We further speculate upon potential factors that could have affected the subjects' learning and performances. Several suggestions in regard to methods that could be used to improve the learning effectiveness of the game have been proposed.