The first sound that struck me as musical is the almost gong-like sound starting at 0:04, after listening to it for a couple of minutes, it reminded me of how pizzicato sounds on a cello. I feel like this sound accomplishes the same task as what a bass drum often does, keep time. At 14:40 this sound truly transforms into a gong sound effect over the background of rain.
The second sound that I believe is musical is the violin at 6:50. It contrasts the gong and the repetition of it is a common arrangement in music. The contrast between the violin and gong create a satisfying texture and gives variety to the soundwalk. It is almost like the chorus to a song.
My third choice of sound is the piano at 42:45. The chord is enjoyable but the delayed fourth note gives an eerie feeling and draws in your attention.