This report describes how the European Commission engaged in developing a serious game in order to engage stakeholders with foresight scenarios created to support the EU policy-making process. Four scenarios were created through a classic scenario building methodology (2X2 matrix), describing possible transitions towards a more sustainable future for the EU in 2035. These scenarios were used as a basis to design a serious game to help players engage in systemic thinking, discover and create alternative futures, and create novel engagements between stakeholders. The game was developed over a four month period and entailed running 10 prototyping sessions involving players from various services of the European Commission and other organizations (industry, civil society, academia, etc.). A system was developed to be able to harvest the stories created during the gaming sessions as a basis for de-briefing, further discussions and strategic analyses after the game. Ultimately, the game has demonstrated its usefulness and value for both players and organizers, and our reflections on the development process offer insights as to game design strategies and how educational outcomes and principles can be effectively mapped onto game mechanics.