Capcom's idea to go retro with Mega Man 9 was simple yet ingenious. Few previous games or game soundtracks have received such hype from such little technological investment. Marketing matters aside, however, the question is whether the finished product is of high enough quality to warrant the technological leap backwards. Though Rockman 9 Original Soundtrack may well win points from some for nostalgia, it neither eclipses the best efforts from the 8-bit era nor does it fare as well with its limited tool set as it would have through more modern means.
The stage themes are the main attraction of the soundtrack and follow a variety of clearly defined themes like fire, water, electricity and space, to which the artists style their synth instruments accordingly. "Concrete Jungle" begins with an apt industrial beat, "Plug Electric" features a cool little electronic warble effect, and the trippy percussive synth instrument in "Jewel Temple" would indeed best be described as crystalline. Though these instrumental accents are impressive examples of creative sound synthesis, the main instrumentation is more in line with what a skeptic would expect and brings the soundtrack back to reality. Synth sax and horns are perhaps the best approximation for the lead instruments that carry almost every track, but in reality they amount to whiny electronic drones.
If you can get past the limited synth the stage themes themselves are actually pretty interesting, and very much would be perfectly suited to sax and horns with their high-energy funk and big band influence. Probably the best of the bunch are "Hornet Dance" and "Thunder Tornado". "Hornet" stays catchy from intro to main theme to chorus, while the hyperactive main melody for "Thunder" leads perfectly into a soulful, jazzy chorus and wailing solo synth.
The tracks preceding the stage themes seem an intentional tribute to the oldest of old-school NES music, but are so mind-numbingly simple they hold little value apart from nostalgia. The soundtrack falters again in the home stretch from a string of simple mini-melodies that do little more than to disrupt the flow of the soundtrack, only to be followed by the Dr. Wily tracks that, while longer, generally don't offer anything interesting technically or melodically.
Still, the latter half of the soundtrack does have its moments. "Shop" provides a bright, groovy dose of synth funk and the super-short but super-hyper "Rush Jet" is worth repeated listens for its catchy "ching!" sound effect alone. "Wily Machine", like "Boss" before it, paints the scenario of a quirky but dangerous "science gone wrong" mechanical experiment on the loose.
Concluding the soundtrack are the closing credits music and the special stage themes. "Staff Roll" would fit right in as the happy, bouncy end theme for a cutesy anime, while "Overdrive Scramble" has one of the catchiest, most energetic melodies of the album. "Maze of Death" does a nice job of combining brief, energetic melodies with a bit of experimentation, though as its "Endless Stage" moniker suggests it does become repetitive.
Ironically it's much easier to appreciate Rockman 9 Original Soundtrack when imagining what it could be were it not constrained to 8-bit. Some tracks would be much more effective were they to combine their best 8-bit instruments with more modern sounds, while others are just begging for a brassy big band performance and some electric guitar. Hardcore game music fans may very well enjoy the nostalgia and energetic melodies, provided they expect merely a good 8-bit soundtrack and not the second coming. Newcomers and skeptics, however, will be better off relegating it to history.