The virus was released by the Church of the New Epoch, a religious group led by a group called "The Nine" and following a religious text known as "The Book of Cataclysm". The Church are seeking to undermine the world rule by corporations in favor of subjecting its parishioners to its own variety of mind control. "Harbinger" was their first step in demolishing the existing world order. The Nine began as the Otherworld Research Group (ORG), a group of top scientists who were researching alien technology found at an archeological dig site near Reykjavik. The ORG went into hiding to continue their research on "The Codex", an encrypted set of alien technological information, subsequently forming the Church.
The bulk of the game concerns the development of armed conflict between EuroCorp and the Church. As insurrections take hold, the player is also obliged to conduct missions to control rogue elements within the syndicate itself, as various sub-corporations change allegiances or make bids for independence.
The game's story culminates in a battle for control of the moon (accessible via a transport system called the "orbital elevator"), with The Nine intending to convert ionosphere calibration equipment located there into a weapon (known as the "ion gate") and destroy all life on Earth; however, The Nine are eliminated, and the weapon deployment does not succeed.
The ironic parallels between the objectives of Church of the New Epoch and the original EuroCorp syndicate itself are abundantly clear throughout the game, further reinforced by the fact that the game can be played from the point of view of the Church itself to similar ends. It is revealed early in the game, when played on the Church's side, that the "disciple" in control of Church agents is a former EuroCorp agent who has been converted.
Gameplay
Syndicate Wars' instruction manual specifically addresses the player as a newly hired EuroCorp executive; however, they can chose to control agents from either EuroCorp or the Church of the New Epoch.
The game preserves the isometric view of Syndicate, while adding rotation and pitch controls over that view. The player commands four agents (or acolytes, when playing as the Church), either singly or in groups, to complete a series of globally-located missions, the objectives for which include assassinating a specific target, or stealing a specific object. Although the general mission structure remains consistent when playing as either EuroCorp or the Church, they are made distinctive by differences in the pre-mission briefings which are delivered to the player in the form of a fictional email system.
During missions, the health, shields and weapon energy (which functions in the place of specific ammunition) of the player's agents will recharge over time. New weapons can be acquired either by picking them up during missions, or by completing research (which is also used to upgrade agents' cybernetic components). Weapons available early in the game include uzis (the default weapon), miniguns, and flamethrowers; however, later stages of the game introduce directed-energy weapons, such as the pulse laser, electron mace, plasma lance, and graviton gun. Other items of equipment available include rocket launchers, gas grenades, explosives, armed drones, and equipment to direct orbital bombardment from satellites.
The 'Persuadertron' device, first introduced in the original Syndicate, is also available (though known as the 'Indoctrinator' when playing as the Church of the New Epoch). This device is used to convert NPCs (both civilians and enemy characters) to follow and fight alongside the player's agents. Some of the game's missions also include objectives to persuade specific characters.
Almost all in-game structures can be destroyed, and in-game currency, for conducting research and purchasing equipment, is acquired through the robbing/destruction of banks, which are located within specific missions. The game also includes the ability for both player agents and NPCs to use vehicles, some of which include the ability to fly over in-game terrain.
Multiplayer
Syndicate Wars supports competitive multiplayer, known as "Multicorp", over a local area network connection, with players receiving points for each enemy agent killed. Mike Diskett (the game's producer and lead programmer) described the multiplayer mode as "a mixture of Quake and Command & Conquer, because you end up with the Quake aspect of just going out there to kill as many people as possible, but you also build bases up. This isn't something we've designed in; this is just how we ended up playing it."
The PlayStation version also allows co-operative play, where up to four players each control an individual agent, using multiple game controllers and a single shared screen.