Enemy Mine is the story of a human and alien trapped together on a world who must overcome their hate for each other to survive. Sounds like an episode of Star Trek, or worse, Battlestar Galactica to me, but extended to a full length movie and directed by Wolfgang Peterson, best known for Bas Boot, Air Force One and The Neverending Story amongst others. In the liner notes, Peterson makes an enthusiastic, but brief comment about Maurice Jarre as one of cinema's finest composers, something I wouldn't dispute.
Jarre isn't exactly known for his sci-fi scores, aside from perhaps Mad Max, but he became (in)famous for his synth scores during the 1980's, as a result of encouragement from director Peter Weir. For Enemy Mine he uses both synths and orchestra in one of his most pleasing efforts. Jarre's synth writing is quite unlike that of say Jerry Goldsmith or more recently Hans Zimmer. Jarre tends to write for a synth ensemble rather than using the electronics to augment the orchestra. The synths are employed to best effect to conjure up both the eerieness of the planet as well as the growing relationship between the two protagonists.
The score (at least based on the album sequencing) is well structured so that it moves from an essentially synthetic score through to a rousing orchestral finale. The orchestra creeps in now and again, most notable during the rousing Spring. Despite the quality of the synth work, I suspect that the distinctive Jarre main theme being played by full orchestra is the section most likely to stick in the mind after the event. However, the synth aspects should not be dismissed, even if they occasionally sound dated today.
The eerie effects he employs here could sometimes be seen as cliché, but like when we hear a theremin in a Bernard Herrmann score, this is the originator of the concept rather than one of the countless imitations. The most similar writing I can think of would be music from the earliest episodes of Star Trek: The Next Generation which mixed the vaguely mystical with more relationship based music. One of Jarre's most approachable synth efforts, Enemy Mine is well worth hearing, even if you tend to prefer his orchestral efforts.