Wikipedia
Marsport
Marsport is a science fiction computer game that was released for the ZX Spectrum and Amstrad CPC home computers in 1985. It was published by Gargoyle Games in the United Kingdom and Dro Soft in Spain. Marsport was intended to be the first part of a trilogy called "The Siege of Earth" but parts two and three (Fornax and Gath) were not forthcoming. Because of this, it is often regarded as being part of an unofficial trilogy alongside Tir Na Nog and Dun Darach (both of which are part of the same official series) due to its having very similar gameplay to these titles. Marsport also has similarities to the later Gargoyle game, Heavy on the Magick.