What is the true objective of panzadrome for the zx spectrum?

The true objective of Panzadrome is to locate and destroy the flashing red and yellow checkerboard squares dotted around the island. The only way to destroy them is to us the mortar weapon as the targets are invariably located in areas where direct fire from your tank's cannon can't hit them. Although most of these squares are placed individually, there is a "Main reactor" complex located in the NE of the island from your starting location. It is heavily defended and can only be reached through a long and difficult route. Almost half the number of targets you need to destroy in order to complete the game are located in a cluster there. I usually leave this complex to the end after all other targets have been destroyed as the red tanks will be very aggressive in trying to defend it, giving you no respite wherever you go...