I found this video • Undertale's "data.win" converted into RAW ... and noticed how the audio is barely audible and all messed up. Here's a "fixed" version where the audio is at 44100 Hz, 16-bit and in stereo.
Audio data starts at 2:42 and lasts until the end.
The line in the middle is the playhead, showing the current position of what's playing.
Most sound effects will play out fine, but some will play at 2x speed (because they're mono).
I used Binary Waterfall (github.com/nimaid/binary-waterfall) for this, not ffmpeg directly.