A couple of classic composers. Both these guys were not just composing and producing some amazing music for games but also they had to pioneer & design the individual sound from the ground up, because obviously they were writing the book as the went along, Tanaka even had the job of designing and programming the sound chip for the Game Boy & the SNES.
Hirokazu Tanaka - Earthbound - SNES
Tim Follin - LED Storm - Spectrum
They may have just been trying to create their favoured genres within the limitations of the new technology and might not have realised it at the time, but they were creating a new form of electronic / techno music that was completely unique.