Space-invader

Space Invaders is a fixed shooter in which the player moves a laser cannon horizontally across the bottom of the screen and fires at aliens overhead.

000

Winner or Loser

The player controls the cannon at the bottom of the screen, which can move only horizontally. The aliens moves both horizontally and vertically (approaching the cannon). The cannon can be controlled to shoot laser to destroy the aliens, while the aliens will randomly shoot towards the cannon.
behavior: The aliens are aligned in a rectangular formation, floating slowly in horizontal direction. As the formation reaches one side, the aliens approach the bottom by a certain amount and start floating in the opposite horizontal direction.
Scores: Each eliminated alien is worth 100 pts.
Game over: When the aliens have reached a certain vertical position (successfully invaded the planet), the game ends and a game over screen is shown in the playfield.