Communication of risk, e.g. posed by floods, heatwaves, or infrastructure failure, intends to reduce impacts, limit damage and ultimately save lives, as well as foster people’s adaptive and coping capacities to future events. Yet risk is a complex, semantically overloaded and at times ambiguous notion, which affects its understanding and management. In addition, risk communication is influenced by factors such as expert/non-expert knowledge exchange, imbalances of top-down approaches, trust, and empowerment. In response to this, participatory and community-oriented strategies, including game-based interactions, have been implemented to support risk management through stakeholder engagement. Joining this conversation about participation in risk communication, this paper presents Risk Response, an adversarial discourse game that facilitates discussion of future environmental, social and technological risks, and appropriate responses to them. The game offers a card-based interaction which mediates (i) conversational play (level I), in which players speculate on risks and imagine responses, and (ii) group modelling play (level II), wherein teams engage in semantically enriched conceptual modelling using ontology-based formalisations. This article describes the background, design and play of the game, with a preliminary evaluation of in-game group modelling enacted during a workshop that demonstrates semantic alignment using ontologies in participatory risk communication.