Gungage is a futuristic third-person shooter where you battle strange creatures from Dark Moon, an alternative world threatening to invade Earth. Start with one playable character and unlock three others, each with distinct traits plus unique psychic powers. The story branches differently depending on your character choice, though all use the same level layouts. Collect special powers throughout missions set in diverse environments from deserts to laboratories, facing enemies ranging from prehistoric beasts to futuristic robots and tanks. Defeat giant bosses to complete each level across easy, medium, and hard difficulty modes.