Alien (Personal Computer News)

The alien ship passes overhead, razing the ground below with its power beam, and dropping swarms of deadly Yeepods. Moving swiftly across your territory you fire your missiles as long as the power holds out. When a recharge is necessary, your base changes shape, and you must ride out the dangers undefended. As an added difficulty, you can choose to have an invisible alien, only identifiable when it fires, and providing minimal guidance for your missile positioning.

Published in the book "Sixty Programs for the Commodore 64".