PlanetSide is a massively-multiplayer online first-person-shooter computer game made by Sony Online Entertainment. It was released in May 2003 and received its first and only expansion pack (Core Combat) in October of the same year.
A guide to install is available here, Requires community contribution to reclaim information on the game:PlanetSide_Installation
Fighting in PlanetSide takes place on the planets of Auraxis.
Sometime in the future man began to colonise the stars under the intergalactic reign of the Terran Republic. Upon discovery of a wormhole that led to an inhabitable planet the Terran Republic began colonising the original planet of Auraxis. Upon this world they found remnants of an ancient alien civilisation: the Vanu. This included new technology such as the warpgates, which allowed instantaneous travel between the continents on which they resided, and rebirthing technology, which can restore a person using their stored genetic pattern if they die. One day the wormhole collapsed, cutting off the expedition from the rest of the Terran Republic. The remaining governement attempted to prevent the news of the wormhole's demise from the population while they attempted to reopen it and re-establish communication with the republic. It used any means at its disposal to keep its secret safe but to no avail. The news fractured the three colonies of Auraxis into three factions. The first remains loyal to the Terran Republic and fights to maintain the law and order its government can provide. The New Conglomerate rose up to fight what it sees as republican oppression of the people while the Vanu Sovereignty took what Vanu artifacts they could to safeguard them for future study. Fighting from their bases of operations, the sanctuaries, and without fear of death the three empires fight for control of Auraxis. For land, for power, forever.
 The Bending
After years of fighting by its inhabitants Auraxis was rocked by a series of progressively violent earthquakes and meteor showers. The events culminated in what is now called "The Bending". Whilst the cause of the bending is unclear, the result was that the continents of Auraxis were transported, in tact, to separate planets across the stars. One exception was the continent Oshur, which did not survive the event and was instead transformed into four smaller islands, which were named the "Battle Islands".
 Player Progression
Players progress through the game by earning Battle Experience Points (BEP), Command Experience Points (CEP), and Merit Commendations. Earning battle experience points causes the player to increase their Battle Rank, allowing access to Certifications and Implants. Squad leaders can also gain command experience points which allows them to increase their Command Rank, allowing them access to tactical overlays, special abilities, and cosmetic armor pieces. Finally, merit commendations appear as ribbons on the players shoulder to show achievements achieved through the game.
Infantry has access to a wide range of weapons including knives, assault rifles, shotguns, Anti-Vehicular weaponry, and mines. Infantry can also carry support tools such as the Medical Applicator, which allows them to heal themselves and friendly soldiers, and the ACE which allows the deployment of turrets and explosives. Most weapons and equipment require certifications to use.
What a soldier can carry in the field depends on the armor they're wearing. All soldiers spawn in a Standard Exo-Suit and have access to Agile Exo-Suit. The lightest armor is the Infiltration Exo-Suit which provides no armor but allows its wearer to cloak, rendering them invisible. Reinforced Exo-Suit (nicknamed "rexo armor") is the heaviest normal infantry armor, but does prevent the wearer from operating the majority of PlanetSide's vehicles. Finally the Mechanized Assault Exo-Suit (or MAX for short) offers the best protection, has specialized weaponry (anti-air, anti-vehicle, and anti-infantry variants) and has access to an empire specific ability (e.g. the New Conglomerate MAX units have a shield). The trade off to this superior protection and armor is reduced maneuverability and versatility.
All vehicles require certifications to spawn and operate. They can be acquired at vehicle terminals located at facilities and the Sanctuary. Certain aircraft, such as the Galaxy, can only be spawned at the Sanctuary or at a Dropship Center. There are vehicles which are operated by a single person, and vehicles that require additional persons in order to operate the gunner or passenger seats.
 Player Organization
While players can fight on their own they can also join squads, groups of up to 10 players, for mutual support and shared experience. As many as 3 squads can band together to form a Platoon. Lastly, longer term relationships are provided through outfits. Outfits have hierarchies of players and custom decals to put on their vehicles and armor.