Despite extensive research, training to overcome cognitive biases has proven largely ineffective. Critical decision-making in the face of uncertainty is difficult because participants employ heuristics that are unconscious and subtle, but which can produce very serious impacts. It has often been demonstrated that even cognitive bias experts make judgment errors by falling prey to the very biases they study (Heuer, 1999). Our team designed and developed a video game to teach cognitive bias recognition and mitigation as an alternative to current classroom methods. Then we performed an empirical study of that game’s learning and training efficacy. The results indicated that the game was effective for learning, but impacts on biased behavior were inconsistent for the different cognitive biases addressed by the game. Additional training aids to reinforce the game learning may be critical in order for it to reliably supplant higher education courses in cognitive thinking. This paper provides a high-level overview of the project and the particular cognitive biases taught in the game. We discuss the blend of instructional theories, techniques, and media used in the game and the results of our effectiveness study. The paper describes the transmedia training package we created to provide a variety of out-of-game experiences which show promise for increasing the learner’s ability to mitigate these cognitive biases. This training package provides: a) an on-going reminder to apply their new knowledge and skills; b) additional practice honing their skills; and c) refresher training to reduce knowledge and skill decay. The use and ratios of the in-game transmedia types and the use of out-of-game transmedia has not been studied yet. The paper concludes with suggested research of the effectiveness of post-learning transmedia.