This pre-release of Cryo's 1992 PC game had a number of elements not in the final game. Based more on the 1984 film than the original book, the retail releases's central character, Paul Atreides, resembled Kyle Maclachlan. However, as you can see in the above screenshot from the demo, this was not always so.
Getting the demo to a playable state is well documented and there are many differences between the beta and final release. But there is less about how the demo plays. As with any beta, there are problems, even with hacks. Talking to certain characters can crash the game, while important places may not show up as they should. These issues can not only interrupt playing the game, but also prevent any progress.
But by making the sietches visible with a hex editor (saves from other versions do not work with the demo), you can at least get access to many (but not all?) of the various places on the planet. You can even visit the enemy forts in the north without being shot down, but there isn't much to see there. I have found various characters like Farah and Chani, but even here, there are glitches and crashes. I hope to get a page up on the main website soon.