Vyper

Vyper is a single screen shoot 'em up similar to Galaga where the player has to save the universe by shooting down large quantities of aliens known as the Yarks. The game can be played by one or two players (in hot seat) and there are 100 different levels and 25 different kinds of aliens. The player controls his space ship down the bottom of the screen and shoot at the aliens above him. Like in Galaga the aliens enters the screen in specific formations before taking their stationary places. After that they then leave the formation, a few at a time, and try to crash into the player. Each alien type has its own movement pattern. The player starts with three ships and after they have been all destroyed it's game over. An extra ship is awarded after every third completed level.