The lander demo is also know as the game Zarch (or Virus for other computers). David Braben (of the Elite[1] fame) wrote that in three months[2] for the release of the Archimedes.

[1] http://en.wikipedia.org/wiki/Elite_%28video_game%29

[2] http://en.wikipedia.org/wiki/Zarch

Zarch, now available for your web browser: https://qht.co/item?id=4052784