Space King is a single-player arcade game in which players control a spaceship at the bottom of the screen, shooting at descending waves of alien invaders to prevent them from reaching the ground. In this game, the setting is outer space, with players defending Earth from an alien invasion by strategically shooting and dodging enemy fire. It stands out with its classic gameplay mechanics that emphasize quick reflexes and strategic positioning, along with its historical significance as one of Konami's early arcade titles inspired by Space Invaders, featuring simple yet challenging gameplay elements.