As far as film soundtracks go, Waterworld is perhaps the most successful combination I've heard of the musically and dramatically complex arranged style of film music with the memorable melodicism and enjoyable accessibility of game music. Anyone who at all appreciates both drama and melody in a soundtrack will find much to appreciate in Waterworld.
The Waterworld soundtrack takes the base elements of the film and works with them musically in a way that far supercedes the film itself. Principle among these elements are epic, mood-setting environment pieces; memorable, emotionally-stirring character themes; and rousing action music. They're the staple elements of any adventure score, be it for film or game, and Howard superbly executes all three.
The environment music consists mostly of either apocalyptic or aquatic themes. From the beginning with "Main Titles", the soundtrack establishes the apocalyptic/aquatic setting through the use of tribal percussion, deep thick-sounding wind instruments highlighted through contrast by fluttering windpipes, and appropriately simple but moody choral accompaniment, to provide an almost entirely unique tone (more on that later). "Swimming" is the shining example of the more purely aquatic sound, providing pleasurable ambience throughout and finishing with an absolutely beautiful flourish of bright percussion and childlike soprano voice.
In addition to the environment and mood music, Howard provides a couple extremely memorable character themes. Most special is the theme introduced in "Prodigal Child", where Howard takes the feelings of child-centered sweetness, tenderness, innocence, and admiration and expresses them perfectly in music, while also revealing epic implications. Thankfully, the theme is used several times throughout the score, including its triumphant culmination in "Dry Land", and it never fails to make an impression.
The other principle character theme is the Mariner's theme, which usually doubles as an action theme. You could literally say it gives the action sequences character, as the briskly-paced background percussion and dangerous-sounding lead orchestrations - good action music in their own right - are brought to engagingly triumphant fruition by the onset of the theme. Several action tracks go without the benefit of the Mariner's theme and - with their Panzer Dragoon-like, slightly tribal upbeat percussion - go above and beyond their required duty.
One of my favorites qualities of Waterworld is its occasional similarity to other favorite soundtrack material. The previously discussed "Main Titles", for example, is the first occasion I've heard of music comparable to that of the renouned Panzer Dragoon series. Its tone is so pleasingly similar to that of the title music for Panzer Dragoon RPG that fans can't help but notice. On a couple extra occasions the score sounds similar to other high-quality game music in tone, like when "Swimming" brings memories of Yasunori Mitsuda's better ambient moments in Chrono Trigger OSV. Then there is "The Bubble", ominous environment music that sounds quite similar to some of Danny Elfman's work in Batman Returns. These similarities can be quite noticeable, but they are only occasional, and for me are very enjoyable bonuses.
Waterworld is a long soundtrack for a long movie, so listening through the entirity is not a brief excursion. Fortunately, the score is broken down quite well into separate tracks, so for the few less-than-great moments or for limited engagements, it's easy to access one's favorite parts.
The soundtrack to Waterworld totally meets the thematical and functional needs for a film while providing enjoyable and memorable music that can stand on its own. There are some slower parts as with any film score, but they do help draw full appreciation for the highlights. Those highlights are numerous and spectacular, and earn the soundtrack a whole-hearted recommendation.