Everything you hear here comes from running the cartridge's own sound engine (SUENA, 0x785D, and SONIDO, 0x77FE, which hands it the three channels; the interrupt calls it at 0x4041) on an emulated Z80, frame by frame at 60 per second, just as the game calls it. What the engine writes to the PSG is turned into sound with an AY-3-8910 (tools/musica.py). Each MP3 is the whole piece up to where it starts again, plus 8 seconds of the repeat fading out; those that do not repeat end where the engine ends.
The PSG writes have been compared frame by frame with those of openMSX (C-BIOS MSX1 japonés). In every frame the PSG ends up the same:
The timbre is not checked: it is a textbook AY-3-8910, not a recording of the emulator. The probes are tools/omsx_psg.tcl and tools/coteja_psg.py.
SONIDO takes the number in A. From 0x8E up it is music (0x8E uses two channels, 0x90 and up three); below that it is an effect, which uses channel C only. Each channel has ten bytes at 0xE010, 0xE01A and 0xE024, and the engine reads one note per event from the track. In the 0x9C fanfare the last openMSX frame differs only because the game asks for it again as soon as it ends.
The start (0x8E)
Asked for by ESTADO_10_ESPERA when a screen starts; lasts 21.5 s and starts again at second 0.2.
Death (0x90)
Asked for by MUERTE_CON_VIDAS; lasts 2.0 s.
Game over (0x93)
Asked for by ESTADO_12_MUERTE when no lives are left; lasts 5.0 s.
Hit (0x96)
Asked for by LE_HAN_DADO; lasts 0.2 s.
Sinking (0x99)
Asked for by SE_HUNDE; lasts 0.6 s.
The finish and menu fanfare (0x9C)
Asked for by MENU_CORTINILLA_BUCLE and META_ALCANZADA; lasts 3.2 s.