Mobile Suit Gundam Seed: Battle Assault is set in the Bloody Valentine War between the Alliance and ZAFT factions.
The game follows eight (plus four unlockable) pilots as they engage in armored combat on the battlefield. Each Gundam can be equipped with either physical close-range attacks or long-range beam/gun attacks, allowing for a variety of strategies to be employed. Additionally, Gundams can boost to quickly move around or change direction mid-air, and enter Berserk mode, which increases their attack power but reduces their armor.
Before starting the game, players can choose to reduce their boosting ability in order to increase their Gundam's armor or HP. The game offers several modes, including a simple story mode, training, time attack, survival, free battle, and 2-player versus for two opponents.