Extremist and terrorist groups are known to have used games and gaming successfully in their online recruitment and indoctrination campaigns. What are the possibilities for using online games to generate resilience against extremism? Current research on online counter and alternative narratives generally acknowledges effects in terms of awareness raising, yet is skeptical when it comes to impact, mostly owing to the limited evidence and empirical research in this area. A related problem with the early counter and alternative narrative campaigns, however, has been not only a lack of initial preparatory work on understanding the radicalization process itself — specifically, on how narratives are produced and disseminated — but also on aspects relating to the audience, the messenger, and the communications strategy more broadly. In designing DECOUNT, an online game that incorporates both counter and alternative narratives, we have taken these aspects into consideration and created an accessible, easy-to-use product by first researching the following: individual radicalization processes; extremist online propaganda narratives and imagery; and the preferences and issues of the target population. We then created and tested the game and placed it on particular social media platforms (Instagram, YouTube/Let’s Play), with appropriate targeting. Finally, we carried out a number of evaluation procedures, including a qualitative assessment and two quasi-experiments. This paper outlines this preparatory, creative, and evaluative work, and contextualizes it within the literature on the role played by online platforms and content both in individual radicalization processes and in creating resilience.