Threats to critical infrastructure are not passive. Trying to identify what is in fact 'critical' is proving to be very difficult as threats constantly evolve. A major benefit of simulating the infrastructure is that security tests and risk modelling can be applied before infrastructure is built or its environment modified, allowing for lower cost design alterations to minimise vulnerabilities. By using the 3D environment of an existing Game Engine we can explore several possibilities for security analysis that existing tools, due to their global view of the problem, do not allow. Providing participants with a first-person view of the situation allows for more realistic role-play, whilst the networked gaming technology allows remote experts to interact in an intuitive environment and explore, identify and assess the critical components of the infrastructure.