As sole composer of Metroid Prime 2: Echoes, Kenji Yamamoto expanded the aural universe established with Prime while giving Echoes a unique flavor. The 'swamp' feel from "Chozo Ruins (Main Plaza)" was expanded to the mournful cries of the masterful "Torvus Bog", and "VS. Space Pirates" returns with tribal intensity while 'Phazon clangs' punctuate "VS. Emperor Ing (Chrysalis)" (the "Spider" form contains homage to Metroid Prime's title theme). Echoes' originality shines through the neon Tron-scapes of "Sanctuary" with its tower chorale and poingnant electronic whistles, and the industrial clanging and insectile scritching of "Temple Grounds". The battle themes also stand out, especially "VS. Quadraxis", which oozes Ing goo punctuated by metallic rumbles, behemoth in size. The best by far, however, is "Title ~ Dark Echoes" with its haunting melancholic nostalgia, a longing to put right some mysterious loss. At the soundtrack's heart is the mix of light and dark, through the airy Luminoth themes and the Dark Aether themes. The latter emphasize atmospheric minimalism, containing distorted echoes of the Light Aether themes ruptured by static discharge and punctuated by the violent dischord of the Ing battles. Atmospheric, but not exactly easy listening.

To please longtime fans, Yamamoto-san arrange classic Metroid tunes, including "Silence" ("Item Room"), "Save Room" ("Tourian"), and "Splinter Hive" ("Gold Statue Room"). There's a watery arrange of "Brinstar Red Soil Swampy Area" in "Torvus Catacombs", the electrical "Multiplayer ~ Hunters" as the beloved "Brinstar Plant Overgrowth Area", and the heart-pounding "Escape" theme from Metroid 1. Finally, "Theme of Super Metroid" makes a pleasant return for the heroic Galactic Federation in "Last Stand".

Like Prime, Echoes contains lots of audio bugs. Once again, audio master extraordinaire PrimeBlue spent long, tedious hours removing them to create the clean audio heard below. I can’t thank him enough for making this the definitive version of the soundtrack. Note track titles have been changed from PrimeBlue's original listing to reflect their American names. The Echoes Demo soundtrack is below.

Most of the demo tracks are identical to the final versions in Echoes. The main exceptions are the "Landing Area", which is an original 'ruins area' type theme similar to the Chozo Ruins from Prime, and a unique "End Jingle", which is a shortened version of "Record of Samus". The demo also contains the Prime version of the Elevator Room theme. The demo was recorded through line-in. Audio tracks were not normalized, but retain their relative in-game volume.