Cataclysm

The Jovians are attacking the isolated lunar settlement of Erriam. It is defended by only a single laser ship, which is expected to only postpone the cataclysm that will be the complete destruction of the colony.

You control the targeting sights of the laser. Waves of around 70 aliens will appear above the colony dropping bombs on the various buildings. The laser can destroy both ships and the slowly falling bombs. Destroying each wave will only delay the inevitable, as reinforcements will soon arrive.

For the Commodore 64 port, at 20,000 points, demon ships will appear and crash down from the top of the screen. These cause great amounts of damage if left unchecked. And from 30,000 points, neutron bombs will slowly float across the screen. These must be defended against falling bombs from the aliens, otherwise it will detonate and wipe out everything.

There are 10 levels of difficulty. This affects the number of aliens on screen at a time, the frequency with which they drop bombs, and the prevalence of demon ships. The game ends when all of the buildings of the colony have been flattened.