Hikoshi Hashimoto is a Japanese composer, sound designer, and audio director. He started out creating music for Sega's arcade game Racing Hero. He then subsequently created music for many of Sega's home platforms including the Sega Genesis and Game Gear. In 1990, he went freelance and worked for various developers and worked on various platforms including the SNES. He also started his own band called DeviceHigh with "REM" and Shigekazu Nakamura. Hashimoto has worked on over 200 games, and continues today to work on music for smartphones. Some of his best known works include Battletoads (Game Gear/Genesis versions), Brave Frontier, School Days, and Cyberbrawl.
For Battletoads, Hikoshi had to learn David Wise's score, and adapt it to Music Macro Language. To do this, he recorded a video of him playing through the entire game, and then adapted all the music and sounds by ear. 
Hashimoto also confirmed doing the Game Gear version of Battletoads, though most sites only credit him with the Genesis version.
To create music and sound on the SNES, Hikoshi programmed his own sound driver. He would then create MIDI files and converted them to his sound driver. He would take into account not to go over 8 channels.
- Hikoshi's official gameography: http://hikoshi.matrix.jp/prof/index.shtml