Star Wars: Empire at War: Forces of Corruption serves as an expansion pack for the original game, Star Wars: Empire at War. Its unveiling occurred at E3 on May 9, 2006. This expansion introduces a variety of new maps and units, alongside a fresh storyline centered on the rise of Tyber Zann. It also presents novel gameplay mechanics, notably allowing players to control the Zann Consortium, a formidable criminal syndicate. The North American release took place on October 24, 2006, and it was subsequently bundled with the core game as Star Wars: Empire At War Gold Pack on Steam on May 25, 2010. This game also marked the debut of Matthew Sloan as the voice of Darth Vader.
The campaign narrative revolves around the ascent of Tyber Zann, an intergalactic crime boss, and his criminal enterprise, the Zann Consortium. The timeline is set between the destruction of the first and second Death Star, culminating in the audacious theft of the Eclipse, an Eclipse-class dreadnought. Zann employs Defilers to corrupt planets, extracting information about rival factions, instigating sabotage, and accumulating credits. Within the campaign, Zann also endeavors to unlock the secrets held within an ancient Sith holocron, which Silri later utilizes to locate the ancient Carbonite Sith Army.
The Galactic Conquest mode retains its core gameplay from the original Star Wars: Empire at War, but with some significant modifications. The Zann Consortium introduces a novel corruption mechanic, granting bonuses to opposing factions alongside those benefiting the Consortium itself. Units sourced from Cantinas and bounty hunters used to neutralize heroes are significantly cheaper on corrupted planets. As an added advantage for the Rebels, smugglers do not expire on corrupted planets. Furthermore, the original Death Star is absent, replaced by its successor following its destruction in the initial game. Similarly, Red Squadron is succeeded by Rogue Squadron. Alderaan is now depicted as an asteroid field. Unlike the original game where it was mod-only, the Executor is now fully playable in Galactic Conquest mode, and is the most powerful combat unit in the game. Moreover, upon a faction's victory (e.g., complete enemy planet capture/destruction, elimination of both enemy leaders, etc.), the game transitions directly to the credits without an end cutscene, a departure from the previous title. This change may stem from the presence of a single story mode (Zann Consortium) with a single end cutscene applicable to both the story and Galactic Conquest, which might not be a fitting conclusion depending on the player's victory conditions in the latter.
The skirmish mode has been adjusted slightly, while still maintaining the feel of the original game. A notable addition is the introduction of 3-faction battles and the option for mirror matches (fighting the same faction).
Land skirmishes now feature a new base-building element: outposts. These outposts can be captured in a similar manner to build pads. Once secured, outposts can construct one of three structures, depending on the faction. The Mining Facility and Hutt Palace are available to all factions, while the third structure is unique to each: Repulsorlift Jammer (Zann Consortium only), Uplink Station (Rebellion only), and M-68 planetary magnapulse cannon (Empire only).
Space skirmishes also bear similarities to Empire at War, albeit with some distinctions. When the Zann Consortium captures an outpost, it can construct a Venator-class Star Destroyer instead of the Interceptor-class Frigate available to the Rebels and Imperials.
While many critics and gamers welcomed the new expansion, some decried it as being overly buggy—one particularly glaring bug that was pointed out often was the announcement of a ysalamiri cage constructing when an enemy fleet was incoming. Also, Garm Bel Iblis's "shield flare" ability can glitch and cause the particle to remain for the duration of the battle. Both of these glitches were fixed in the 1.1 patch.
An equally noticeable, although less frequently mentioned error, involved the Imperial Bp.2 Anti-Infantry Turret, where only the cannon barrel rotated when targeting and firing upon nearby enemies, whereas the entire turret top rotated correctly in the base game, suggesting a potential oversight.
A campaign-specific bug also existed, causing players to lose their main characters and become unable to progress, which was subsequently addressed in a patch.