Flight simulation is an artificial re-creation of aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external environment such as air density, turbulence, cloud, precipitation, etc. Flight simulation is used for a variety of reasons, including flight training (mainly of pilots), for the design and development of the aircraft itself, and for research into aircraft characteristics, control handling qualities, and so forth.
As you would expect from primitive hardware like the CPC. the early flight sims do not match up to their contemporaries today but they can still provide plenty of fun.