The story of Forged Alliance begins in the origins of the Aeon, one of the original Supreme Commander factions. The Aeon have their origins in humanity's sole contact with an alien race called the Seraphim. When the contact went bad, the resulting conflict ended up with an entire planet full of dead extraterrestrials. The Aeon was formed to adopt the aliens' culture into human society in recompense for humanity's crime. Now, however, it turns out that said planet wasn't the Seraphim's home; it was just a small colony of a much larger empire. Now the Seraphim have opened a gate into human-controlled space and discovered what happened to their long-lost brothers. Needless to say, they're pissed and they've decided where humanity failed at universal genocide, the Seraphim will succeed.

The story of humanity's battle with the Seraphim will play out in a brand-new single-player campaign that details the triple alliance of Aeon, Cybran and UEF battling against the first truly alien presence in the game. While the Seraphim won't be playable in single-player, they'll certainly throw a few monkey wrenches into tried-and-true strategies with over 100 new units including a really cool experimental bomber that darkens a big chunk of the sky before it brightens up the area with negative energy bombs that are basically mini-nukes.

Not to be left out, there are some fun new toys for each of the game's original three factions. The UEF is getting a 3-point defensive emplacement that will help defend against ground assault. The Cybrans should enjoy a shout out to Total Annihilation, the Brick, a mobile missile launcher that shoots torpedoes in the water and lasers on land. The real fun for the Cybrans comes in the form of their new experimental megalith. This crab-like monstrosity is amphibious and can blow away entire navies. On land it moves slower but acts as a mobile production platform that can drop armies on the run. The resource requirements for these giant units have also been reduced so players should finally start seeing them in multiplayer matches.

Some of the most important additions to the game, however, won't be immediately obvious from the screen. The game's new AI is apparently way, way smarter than the one that shipped with the original version. According to Gas Powered Games personnel, in internal testing it's been able to beat the old AI in about 10 minutes with much less of a performance hit. The game will ship with unit shaders that make everything shinier and cut down the drag on performance. Aircraft get a new flight dynamic model, the sky dome's been revamped and the user interface has been re-done and can now be skinned and reorganized with faction-appropriate art.

(qtd. from Gamespy.com)