[9] The game's setting and story takes place in an alternate 1989, in which an impending economic collapse and the failure to achieve aid diplomatically from the West, leads the Soviet Union to invade Western Europe, triggering World War III.

The single-player story sees players assume the role of a United States Army officer who takes command of battalions of US and NATO forces; the main bulk of their operations focus on combating a surprise invasion of the United States from Seattle, Washington, as well as operations in Southern France, Russia, and New York.

[15][16][17][18] World in Conflict focuses on real-time tactics (RTT) gameplay, in a similar manner to Ground Control, a game also developed by Massive Entertainment,[8] in which players deploy units onto a battlefield and must carefully make use of them to achieve victory, making use of support assets to further assist them.

Players can also use a messaging system that is designed to allow conversation between individuals regardless of whether they are on the same server or playing the same game.

The single-player campaign places players in the role of Lieutenant Parker (voiced by Alec Baldwin), a United States Army officer, who takes command of a company of troops from both the US and NATO and who narrates the events of the game's campaign prior to each mission; he neither speaks during missions and cutscenes nor is his face shown.

The narrative of the single-player story owes much of its inspiration from both the Call of Duty and Medal of Honor series (see the 'Influences' section below) Multiplayer games support up to sixteen players and can be played on a LAN or over the Internet.

The online component of the game uses the in-game massgate system, which is derived from Ground Control[citation needed].

The system helps players keep track of friends, allowing them to see whether they are online or playing a game.

Players can increase their rank and leaderboard position in a way similar to Battlefield 2, by accumulating earnings and scoring points, medals, and badges.

Lieutenant Parker, the player's character, joins Captains Mark Bannon and James Webb in the retreat from the city under Colonel Jeremiah Sawyer, who held previous commands over all three.

Under Sawyer's command, the Soviet advance is temporarily stalled, and the U.S. manages to win a tactical victory in the town of Pine Valley with intervention from the USS Missouri.

By Christmas, Soviet troops launch a new offensive to capture Fort Teller, the headquarters for the Strategic Defense Initiative.

Sawyer is granted clearance to detonate a tactical nuclear missile above the Soviet formations, retreating just before impact.

Several months prior to this, Colonel Sawyer is deployed to Southern France to assist NATO forces with American reinforcements in driving the Soviets out near Marseille.

Parker, fresh from his training is taken under Sawyer's command, as well as Bannon; presented as arrogant, cocky and eager to fight.

But before this can happen, the battalion is rerouted to New York City to assist U.S. Army Rangers in recapturing Ellis, Governors and Liberty Islands from Spetsnaz commandos.

Returning to the immediate aftermath of the nuclear detonation, Parker contacts Webb and several friendly and hostile stragglers before reuniting with Sawyer.

[19] In early 2016, online multiplayer functionality and a new community-run Massgate were restored by a group of players unaffiliated with Ubisoft or Massive Entertainment.

[22] Those who had preordered the game were given access to the Beta, the ability to preserve their username and clans, and either received the Modern Marvels: Strategic Air Command or the Declassified: The Rise and Fall of The Wall DVD by the History Channel depending upon which area of the world one was situated in.

[5] In PC Gamer (UK), Kieron Gillen singled out World in Conflict's multiplayer, praising the cooperative mechanics and the in-game communication system; while calling the single-player campaign "fun[...] but not exactly deep.

Soviet Assault was also released separately as a download for owners of the original World in Conflict, through Steam and D2D and also in a retail version.