A stand-alone; while other Dune games are entirely based upon war strategy, this one is primarily an adventure.
Which is not to say that the aforementioned elements found in the Genesis version are nonexistent in this one; they are indeed there, but sending out the troops and mining spice take days (game time) to actually see the outcome of the strategy.
The gameplay is similar in ways to Deja Vu for the Nintendo, with a menu taking up the lower portion of the screen used to navigate the environments throughout the game, and multiple choice options to communicate with other Dune characters. You have the option to save at virtually any time during gameplay.
You travel to various locations throughout the large planet of Arrakis using the Ornithopter; if you'd like, you can watch the flight there, with a small map to allow you to see how close you are. Otherwise, you can skip the flying scenes (provided your ornithopter isn't under attack for flying too close to enemy territory)
Another unique feature that Dune enthusiasts will find fascinating is that, while in the Atreides house, you can look in the mirror and see how spice has affected your character, Paul Atreides.
I recommend finding a copy of this game if you own a Sega CD; the music by itself immerses you into the gameplay, not to mention the intriguing story elements based upon the novel and films. I, myself, played the game before ever seeing the 70s film, or its modern remake, and enjoyed it all the same, if not more, since the story arcs and plot twists were all very new to me.
Blessed Be