Hirokazu Tanaka's sound design for the video game Metroid (1986) was unconventional for the Nintendo Entertainment System (NES) in many respects. Aside from his innovative uses of the NES's audio hardware to create timbres reminiscent of electronic art music, Tanaka consistently blurs the boundaries between music and sound effect, between organic and electronic sources, and between diegetic and non-diegetic sound. Using as a model the electronic score of the 1956 film Forbidden Planet, in this chapter Gibbons explores how Tanaka's "cybernetic' sound design both reflects Metroid's science-fiction narrative and resonates with 1980s preoccupations with the electronic nature of video games.