The story follows Big Willy Unleashed, an alien who has come to Earth with a mission to destroy it. He is sent by his Overlord to wreak havoc on human cities and towns, but things don't go as planned.
Players control Big Willy Unleashed as he uses his mind-control device to bend humans to his will, causing chaos and destruction wherever he goes. With a variety of weapons and gadgets at his disposal, players must navigate through levels, avoiding obstacles and enemies while trying to complete their objectives.