The film is shot in contemporary news-style in black-and-white and runs for only 50 minutes. It covers a period of some four months from the days leading up to nuclear attack. The film's war is started following the Chinese invasion of South Vietnam, after which the tensions escalate until NATO pre-emptively strikes at the USSR, who return fire.
The film has several strands - a documentary-style chronology of the main events; an intermittent set of vox pop contemporary interviews; and fictional interviews with key figures as the war unfolds - all twisted together throughout the film.
The action is concentrated on the town of Rochester in Kent. The film depicts the chaos of the build-up to the attack when there is the enforced evacuation of the urban population, and then the immediate effects of the nuclear strike. The rest of the film 'documents' the collapse of society and then civilization in the radiation-sick and psychologically damaged population of the aftermath.
Compared to more modern films such as The Day After (1983) or Threads (1984), the mix of drama and documentary in The War Game, both with a documentary look, has a different and disorientating effect compared to the more conventional later films.