QS Invaders

QS Invaders is a clone of Space Invaders and plays the same as the original. The player controls his laser cannon down the bottom of the screen and has to shoot the alien invaders that move back and forth above him, while at the same time avoiding their fire. Three shields offers some protection. Occasionally a saucer worth a large amount of points will appear at the top of the screen. As the invaders decrease in number they will speed up and once they reach the baseline the game is over. The game is also over when all three of the player's laser cannons have been destroyed. Prior to starting a game, the player can choose from three different difficulty levels.

Without a CHR$ board installed on your ZX81, you can only get simple ASCII graphics on the game, but the gameplay is still the same.