Super Robot Wars Alpha Gaiden

Super Robot Wars Alpha Gaiden (スーパーロボット大戦α外伝, Sūpā Robotto Taisen Arufa Gaiden), often shortened to Alpha Gaiden, is a PlayStation game that launched in Japan during 2001. As the first side-story in the Super Robot Wars Alpha series, it picks up where Super Robot Wars Alpha left off. The title marks the debut of characters from After War Gundam X, Turn A Gundam, and Combat Mecha Xabungle.

The game features the final appearance of the Masō Kishin "Banpresto Originals" in the Alpha series. Aside from Masaki Andoh with the Cybuster, Shu Shirakawa with the Granzon, and Lune Zoldark with the Valsione, these characters would not return until the Masō Kishin universe was revisited in the OG Saga update of "The Lord of Elemental" and its sequel "Revelation of Evil God." While many fans believe this was due to a copyright dispute with Winkysoft, the series creator stated in an interview that he simply wanted to focus more plot attention on other original characters, since the previous games had already covered the Masō Kishin stories extensively. Alpha Gaiden also introduces Sanger Zonvolt, who later becomes one of the selectable protagonists in 2nd Super Robot Wars Alpha.

In terms of gameplay, Alpha Gaiden is the first game in the series where all of a unit's weapons upgrade simultaneously—a system used in nearly every subsequent game except the Original Generation titles. It also introduces the Support ability for both Attack and Defense, letting adjacent units attack together or defend each other from incoming strikes. This feature, too, became standard in most later games.

The story begins shortly after the events of Alpha. The Earth Federation has covered up much of the climactic battle with the Aerogaters, but a gravity shock wave from the Excelion's detonation (from Gunbuster) during the Battle of the Solar System's Absolute Defense is racing toward Earth, threatening to destroy the space colonies and the planet itself. The only hope is the Aegis System, which could shield the Earth Sphere. However, the heroes are thrown into an alternate future where the wave has already ravaged Earth. Facing a new enemy called the Ancestors, they must find a way back to their own time and prevent this dystopian future from happening.