Space Invaders (PS1)
Space Invaders is a two-dimensional shooter game in which the player controls a laser cannon by moving it horizontally across the bottom of the screen and firing at aliens. The aim is to defeat five rows of eleven aliens—some versions featured different amounts—that move horizontally back and forth across the screen as they descend towards the bottom of the screen. The player defeats an alien by shooting it with the laser cannon—also earning points. As more aliens are defeated, the aliens' movement and the game's music speed up. Defeating all the aliens brings another wave that is more difficult. The aliens attempt to destroy the cannon by firing at it while approaching the bottom of the screen. If they reach the bottom, the alien invasion is successful and the game ends. A special "mystery ship" will sometimes move across the top of the screen and will award bonus points if destroyed. The laser cannon is partially protected by several stationary defense bunkers—the number varies by version—that are gradually destroyed by alien fire.
The Playstation version used the basic concept of the original game, but instead of ending only when the player lost to the aliens, it was possible to win the game. The player fights over the planets of the solar system fighting off 10 waves of aliens before fighting a boss. Upon defeat of the boss, the moved on to the next planet.
Upon defeat of the game, the player is given a big ceremony, while what appears to be the mothership returns to the GRAND mothership, and then begins the REAL invasion of Earth.