How these were made

They were not recorded off an emulator. They are rendered straight from the game's own score -- the same note data the ROM plays -- so a track here cannot drift from the track in the game.

The notes, their order and their lengths, the frequencies, the volumes and the stereo placement all come from that source, and playback runs through a 32-step wavetable, which is what gives the Virtual Boy's sound chip its grain.

One caveat, stated rather than hidden: of the seven wave shapes, four -- square, triangle, sine, sawtooth -- are reconstructed exactly, because their 32-step definition leaves no room for choice. The other three, organ, glockenspiel and piano, live in an engine component outside this project and are approximated by harmonic series. Every track that uses one says so above.