Two decades after Godzilla: Save the Earth, a meteor shower strikes Earth. Crystal formations begin growing from the ground at the impact sites, causing climate shifts, earthquakes, and increasingly erratic behavior in the monsters of Earth. Four factions emerge among the combatants—Earth Defenders, the Global Defense Force, alien Vortaak invaders, and a Mutant faction—each with their own objectives regarding the crystals. The source of the crystals is eventually revealed: SpaceGodzilla, attempting to escape the alternate dimension he was imprisoned in at the end of the previous game. Godzilla Unleashed: Double Smash is a two-player brawler for the Nintendo DS, adapted from the console Godzilla Unleashed release.