Aliens is a shoot'em-up game for high-resolution only. Just like in Space Invaders you control a spaceship at the bottom of the screen and fire at enemies at the upper part of the screen. Enemies enters the screen from left or right, some will move around the upper parts of the screen a while before they start to descend while others will aim for you directly. If any of the enemies hits you or the ground you lose a life. There are 20 types of enemies and once destroyed they give you 50 to 300 points depending on type.