Recent disaster events, like the 2021 flood in Germany showed clearly, that even the best alert systems and top first responder organisations can not prevent fatalities and serious damage on property without having prepared the citizens how to act and react during disaster situations and crises, understand alerts and follow instructions. B-Prepared offers a cost-effective solution for building a culture of disaster preparedness with a multi-actor approach in realistic historical scenarios. B-prepared builds on a freely accessible massive collaborative knowledge base and data hub, demonstrating its usefulness via three demonstrator applications: a cooperative multiplayer VR serious game, simulating real disaster scenarios for the safest near-real experience; an interactive gamified mobile app with age-appropriate content and enhanced accessibility to people with specific functional needs for the widest possible reach; and an LMS system to effectively and comparably measure preparedness levels achieved by VR and/or mobile users on a unified scale. Players can take different roles to solve puzzle tasks in an immersive experience. Teamplay, collaboration and communication are keys to survival, strengthening the culture of mutual assistance and cooperation in danger. Player behaviour and gameplay logged in a privacy-preserving way helps collect data on in-game behaviour which serves assessment of preparedness but will also be shared with other synergic research in the same field. A large-scale virtual reality hackathon series will demonstrate its features. The open beta will be publicly available as a giveaway, inviting stakeholders via direct outreach. After closing beta, the game will be available in a non-profit freemium model where in-game purchases are replaced by in-game donations for relief organizations, with a small percentage kept for maintenance and further development.