A typical space shoot-out game with a few novelties.
Using keyboard or joysticks, you must guard the earth from the Zargon fleet, consisting of motherships, attack ships, diving ships, missiles and pods.
This gives you plenty to zap away at, and you can also dig holes in your defence wall to trap the falling pods before they mutate into indestructible motherships.
The graphics are well up to standard, with clearly-defined and easily-identified ships. The speed of ths hips is impressive, and the sound is good too.
During loading, there's a catchy little tune, which will never make the Top Twenty but passes the loading time. After about 10 or 20 loads, the tune really starts to grate on the nerves.
But that's a minor criticism of a good value game that's better than most.