While re-establishing his headquarters, Tyber goes to Yavin IV after the Death Star destruction, where he learns of the Emperor's hidden treasury vaults and designs for a new Super Star Destroyer. The four of them then escape aboard the Millennium Falcon. The actual campaign story begins with Tyber Zann, the leader of the Zann Consortium, being rescued from imprisonment on Kessel with help from Urai Fen, his loyal friend and lieutenant of the mercenary army he built over the years Fen himself arrived on Kessel with the help of Han Solo and Chewbacca. The tutorial mission sets up the main campaign plot, showing Tyber Zann's imprisonment for stealing a Sith artifact from Jabba the Hutt. The campaign story begins just prior to the Battle of Yavin as the game progresses, events from the Star Wars films occur, such as the Battle of Endor. Many of the new units and planets included in the game are incorporated from the Star Wars expanded universe. These include three phases of the Empire's Dark Trooper, Lancet Aerial Artillery, the TIE Defender, and the Super Star Destroyer Executor. New vehicles are also available, most drawn from the books and comics taking place after or between the original saga. Some planets now have infantry- and light vehicle-only terrain, and damaging terrain.

Alderaan is now an asteroid field and Bespin has a new ground landscape. Corruption includes 12 new planets: Dathomir, Mandalore, Hypori, Myrkr, Felucia, Honoghr, Kamino, Mustafar, Muunilinst, Saleucami, The Maw, and Utapau. The skirmish mode includes maps for the new planets alongside the previous maps, with the optional feature of having a third player on the map. The Galactic conquest mode includes new planets, with the added feature of non-conquest goals. Corruption also introduces the ability to position structures and units on a planet's surface, pre-select starting units during space or ground battles, mobile build pads and transport ships for ground battles, the ability to repair space station hardpoints, and orbital bombardment from capital ships. The Rebel Alliance and the Empire receive new units and changes to existing ones. Crowd-pleasers include Rancor riders, surviving Droidekas and, if a 'slavery' mission is performed on the forest moon of Endor, suicide bomber Ewoks. It also has a mish-mash set of original units: A ring of raiders, renegades and ruffians eventually expands to eclectic exotic equipment as the Consortium appropriates everything it can lay its hands on. Several mission types cause a small battle. Its specialty is 'corruption': it can conquer planets traditionally, but also gain bonuses from enemy-controlled worlds by having its infiltrators conduct any of several kinds of missions such as bribery, sabotage or piracy.

The Consortium has a full-fledged campaign that is set in the background of the original film trilogy. The Zann Consortium is a new faction, neither good or evil, but willing to go to any lengths for a profit. Pirates had previously been present in the game, but as a type of moderately-armed 'speed bump' to progression in the war between Empire and Rebellion. Star Wars: Empire at War: Forces of Corruption adds the organized crime syndicate the Zann Consortium as a third faction.

A screenshot of the Galactic map during gameplay (playing as the Zann Consortium) showing multiple planets under an effect of corruption

Star wars forces of corruption maps