The story of Cosmo Police Galivan is set in a futuristic, sci-fi world where the player takes on the role of a Cosmo Police officer tasked with stopping an alien invasion. The game follows the officer's journey as they explore an interconnected world, fighting against various enemies and bosses to uncover the secrets behind the alien threat.
Gameplay in Cosmo Police Galivan is action-packed and adventure-filled, with a focus on exploration and combat. The player can collect power-ups and upgrades, such as new melee weapons and abilities like jet boots that allow for temporary flight. Energy, known as CP, must be managed carefully as it's used to activate these abilities. As the player progresses through the game, new paths and areas become accessible, offering a sense of progression and discovery.