The music

Every piece comes from running the cartridge's own sound engine (tools/musica.py with tools/motor_musica.py and tools/z80run.py): it is asked for with pide_sonido (p00:4D6E, which maps banks 4, 5 and 6 and calls p04:6472) and every frame p04:6978 is called, as the interrupt does. That gives the PSG and SCC writes of every frame, which are mixed into an MP3. The ones that start again are heard twice and fade out.

The check

The writes were compared with openMSX's, register by register (tools/omsx_psg.tcl and tools/coteja_psg.py):

the Konami logo tune (0x4E), 193 frames, and the title (0x2E), 132, in the intro: PSG and SCC the same in all of them;
the tunes of the seven stages, some 375 frames each, three times per game: the same in all of them. To hear each one in its place, the probe uses a copy of the ROM where the header of the stage 1 tune points to the piece's (tools/rom_musica.py). As the effects play on PSG channel C and the first SCC channel, the tune's channels are compared;
the boss tune (0x21) and the item tune (0x22), three times each, and the two endings (0x30 and 0x31), once, some 375 frames: the same in all;
the between-stages tune (0x2F) and one of the stage 7 (0x19) runs differ only in frame 0, in PSG register 1, which keeps what the previous piece left;
the take-off (0x28), 72 frames: the same.