Invader from Space

It’s an invasion from Outer Space and you must defend your missile
bases on Earth from the computer-controlled space invader attack.
You have 5 missile bases and 5 chances to launch a counterattack.
Watch out, here they come. Fire.

It’s a game of speed as well as skill. If the invaders reach the Earth’s
atmosphere, the game is over even if you have missile bases left.