Gorf(1981)

Gorf actually consists in the Arcade version of five different types of space shooters. The first one ist basically is a Space Invaders clone. In the second one a formation of space ships is hovering at the top of the screen while single space ships will disengage from the formation and dive down at you. The third variant is a Glaxian clone and only available in the Arcade version. In the fourth mini-game the enemy will come out of a circular hyperspace field and attack you. After having destroyed four of your attackers the game proceeds to the fifth game stage. Here a huge mothership is dropping bombs at you from the top of the screen. You defeat the mothership with a well placed projectile hitting it between its two major sections. After that the game starts from the gebinning on a higher difficulty level.