Jun Senoue and Kenichi Tokoi on Sonic Adventure Original Sound Track:

Heartless Colleague …for Boss: E-Series Targets

Senoue: There are also boss battles of fellow robots and I tried to decide on the more minimal feeling with artificialities than other music of boss battles. I think that a unique waviness appears.

Tokoi: With whammy bar, the guitar’s unique lowered pitch of the chord of every four bars is nicely reflected in the background with minimal feeling.

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