An exceedingly difficult, arcade style, shoot-out game. Horrible little droids insist on removing a series of shields which support three large and deadly trioxin bombs.
If they succeed, then you are immediately relieved of one of your three lives.
Other ways to disaster are to be hit by the discarded lead shields as they drop, or machine gunned by one of the remaining few droids, which start moving at an incredible rate when most of their colleagues have succumbed.
The droids have a further advantage in that they appear to scroll sideways round the screen whereas you are forced to move left and right to intercept them.
It is well worth the effort to clear the first screen, though, as a pleasant tune is played and you are rewarded with an extra life. Second and subsequent screens are in a different colour set.
There are two versions on each cassette - joystick, or an even faster version using arrow keys and space-bar.
Loading was always successful with no need to use the back-up copy on the 'B' side. The choice of colours means that a black and white TV set can be used if necessary.