Players are given a 1980s vector graphics computer-themed world map, a varied arsenal of nuclear and conventional weaponry, and a primary objective: destroy as much of the enemy's population as possible while having as little of one's own population destroyed as possible. A typical game will see civilian casualties numbering in the millions (megadeaths) while players try their hand at annihilating their opponents.
In most games, all sides take heavy losses. "Nobody wins, but maybe you can lose the least." Games last 30 to 40 minutes while real-time gameplay can last more than eight hours. Game time can be varied by a consensus among players configuring the speed at which events progress from real-time.
DEFCON is a streamlined real-time strategy game, with no unit production, resource collection, or technology tree upgrades. Players choose and position their forces at the beginning of the game on one of six territories, North America, Latin America, Europe, Africa, Russia, or Asia. A countdown system prevents games from disintegrating prematurely. Gameplay begins at alert level DEFCON 5 and counts down to DEFCON 1, and the use of nuclear weapons Each upgrade in alert level brings more possibilities.
Ground installations are immobile, and can be destroyed by nuclear attack. They include missle silos, airbases, and radar.
Naval units are organized into fleets of up to six ships which move and fight together. Fleets must be placed in territorial waters at the beginning of a game, but may move through the ocean, albeit slowly. Fleets can include any combination of battleships carries, and submarines.
Aircraft are launched from either airbases of carriers. Typically they operate autonomously after launch, but bombers and fighters can also be controlled while airborne. Bombers carry a single short-range ballistic missile that may be fired at a nearby target. Bombers have a long range to deliver this payload, but are vulnerable during the trip.
Missiles deliver a devastating payload. A direct hit on a city will kill half of the current living civilians. Between one and three hits are required on the hardened buildings that players place to destroy them. Missiles can only be shot down by silos in defense mode, which have a small random chance of hitting the missile with any given shot-a hit will cause a limited detonation in the missile, yielding minor casualties if a city is directly beneath, or damaging or destroying a facility if one is below. Once launched from a silo, submarine, or bomber, missiles cannot be retargeted, though they can be disarmed in mid-flight. Missiles can also target sea-based units and will destroy any aircraft caught in their blast radius.
DEFCON uses a real-time line of sight system common to traditional RTS games, where only enemy units within radar coverage may be seen. However, a nuclear missile launch from a silo or submarine is automatically detected by all players (though the missile itself is not, and must be detected by radar), which reveals the location of the unit launching the missile. A nuclear missile launch from a bomber, however, does not reveal the location of the bomber. Making it the perfect first strike vehicle.
Most units have several operating modes for different functions, and require several minutes to switch modes. For instance, ordering a missile silo to switch from offensive launches to missile defence will leave it inoperative while it switches. Signaling to other players the perfect time to attack.
A DEFCON game can host up to six human or AI players. Alliances can be formed, broken, or renegotiated at will with human players. Alliances with CPU controlled players can only be set at the start of the game. Allied players share radar coverage and line of sight, but there is no allied victory and there is only one winner. This means that almost all alliances are broken by the end of the game. Lead designer Chris Delay explains:
We've seen alliance members shooting overhead friendly planes down because they believed the planes were scouting the area for targets in preparation for a strike. This results in arguments in the chat channels, followed by skirmishes at sea, followed by retaliation, before finally the whole alliance collapses and everyone starts nuking the hell out of each other. It's awesome.
DEFCON is an awesome game. Like Risk, only with nuclear weapons, everybody starts out with the same chances, the same units, and the same belief they will survive annihilation. Only luck and strategy set a victorious player apart from his conquered peers. The stark isolation of the vector graphics, and the bone chilling audible gasps of the dying, brings the faceless reality of nuclear war to player in a way rich texture maps, and dynamic lighting never could. With each pulse of white light representing a nuclear explosion players know millions of virtual lives have been lost, but the real fear comes from the fact that there is very little separating DEFCON from the way a real nuclear war would be fought. I highly recommend DEFCON to anyone who grew up fearing the nuclear bomb, or wanted to be that kid from WarGames, unknowingly ready to start a nuclear war, if only on the Internet.