Space Tactics

Space Tactics was produced by Sega in 1980.

Defend your bases by shooting the oncoming alien swarms.

This game is a take-off on Space Invaders, but with a number of interesting twists. You start off with five bases at the bottom of the screen that you defend with your laser. A shield with limited renewal capability is also available to further protects these bases. Each base is also capable of firing a large single shot.
The alien ships attack in a dizzying 3-D pattern, but what sets this game apart is that instead of moving your cross-hairs around the screen, the entire screen is motorized and moves to fit within your cross-hairs! It gives the effect of a very large screen with smooth scrolling.