Playing Defcon: Everybody Dies is like watching the final scene of the 1983 movie, War Games. A bunch of people stand in front of a giant screen while a computer repeatedly plays out a thermonuclear apocalypse. Except instead of watching in horror, they're cheering the destruction. Defcon is that final movie scene transformed into a fully functional game. True to War Games fashion, no one actually wins in a global thermonuclear holocaust, but they can settle for losing the least.

Defcon is a multiplayer-focused game that is available for online purchase only, either through the developer's website or through Valve's Steam service. The goal of the game is quite simple: To end the world, causing the most casualties while taking the fewest losses. This easy philosophy carries over to the game's design. There are no heavy 3D graphics; the entire game is composed of line-art images, similar to the developer's last game known as Darwinia. The game is also incredibly easy to learn. Divided into 5 phases (each roughly 5-8 minutes each), players need to set up radar stations, airstrips, naval forces and missile silos, then scout enemy territories for strategic targets. When the countdown reaches defcon 1, the missiles fly.

The simple design masks how complex the game really is, just as how its mellow soundtrack disguises the player's ultimate goal. Above all, players need to protect their radar towers (which detect incoming attacks) while destroying their opponents'. This is actually a lot more challenging than it sounds. Missile silos can either fire short-range anti-air rockets for protection or launch nuclear ICBM's across the globe. They can only be set to do one or the other, and each contains a limited quantity of nuclear missiles which are launched one at a time. Players need to decide which ones to use for defense or offense. Anti-air missiles are pretty fast and will make short work of incoming nukes and planes. The best way to circumvent them is to put more targets in the air than they can handle (using some as cannon fodder), or by destroying their radar stations, lessening the response capability.

Eventually, destroying the missile silos themselves will become necessary (especially when they start launching nukes at you), and they will require three successful nuclear hits if entrenched. Airstrips can launch short range fighters to act as scouts, distractions, or anti-naval forces. They can also send out long-range bombers that deliver a nuclear payload. Unfortunately, even though the icons seem to indicate that they are stealth bombers, they have no cloaking whatsoever. There are three different types of naval ships, each using the rock-paper-scissors strategy. Most notable among them are the nuclear submarines, which can be parked off an opponent's coast and launch nuclear weapons from there. Carriers can drop depth charges to deal with those submarines or launch planes in the air, including nuclear bombers. As to be expected, Defcon is full of ways to nuke opponents into oblivion.