Dark Side/Demos
There are a number of Dark Side demos for different platforms, all of them are interactive. Demos will allow to play a couple of areas and challenge the player to get some maximum score. These demos, as well as other Freescape games ones, can be freely downloaded here.
ZX Spectrum demos
Crash magazine (issue v.1 #54, July 1988). This demo offers five full areas to explore, all of them from the original game.
DOS demos
PC Plus (issue #25, October 1988). This demo offers five full areas to explore, including one specifically designed for this demo. Allows EGA, CGA and Tandy.
Additional options
Using the option "disable demo mode", ScummVM allows to interactively visit the areas in the demos. While the demos do not include the full game, it is currently unknown how complete are in terms of data/scripts included.