Round-37 is fighting off Gigandes during the final boss battle.
Gigandes is a titular antagonist and the final boss of 1989 horizontal side-scrolling shoot 'em up arcade game of the same name. It is a dimensional, suggestively demonic creature who suddenly rises up in the deep place of the Earth's surface and summons its own worshippers and space army from various galaxies to the milky way in order to take over humankind as its main plans. However, the Earth's defenses build a small, powerful spherical spacecraft called Round-37 and their intent is to stop Gigandes and its evil ways, fighting its minions and protect the influences on earth and in outer space.