This fast machine code version of Defender requires a joystick to control the elevation and forward/reverse speed of the space ship.
There are two versions of this game on the cassette: one in the highest resolution and therefore in black and buff and the other which allows for a display in more varied colour. There was little loss of quality in the coloured version, which I preferred as it made identification of the different forms of invader easier.
Your mission is to protect the Caloxin crystals from the Praetorian Invaders. Other hazards hit you from all directions as you fly around by the seat of your pants dodging, diving and dealing out death.
This was a very fast game that required split-second timing - very close to the arcade version. The sound effects, explosions and splintering fragments added greatly to the overall quality of presentaton.
My eight-year-old son retained the highest score, standing at 12,000 points, and my 7,000 looked pretty meagre by comparison. Very entertaining and highly motivating: if you like arcade games, buy it.