DEFCON is a unique RTS from British Introversion Software, known for such experimental projects. The user interface is minimalistic and simple: it resembles a tactical card stylized as Cold War films such as Dr. Strangelove and WarGames.

The game is divided into Defcon phases in which players need to place military forces on a real world map. There are aircraft carriers, submarines, air defense and other equipment capable of either launching a nuclear warhead or reflecting it. The winner in the match is the one who most effectively bombarded the enemy territory. Defcon is a game about pure gameplay, there is no history, as there is no story campaign.

In addition to playing with AI, a player can compete with real people online in multiplayer matches. In total, such matches can accommodate up to 6 people and this significantly complicates the gameplay. Opponents should guess the location of the rival's troops and inflict the most accurate nuclear strike.