I tried the game on Windows to hear the sound. There's sound effects for walking, rowing, picking up stuff, putting down stuff, there's also one for talking to people or picking up flowers. What could be improved about them? I guess I could have wanted the different islands to have different sounds unique to them, but maybe that could have been different music tracks rather than sound effects.
The music, I felt like it fit the game. Not too fast or too slow, and sorta casual-sounding. But just like the graphics with too-light and too-dark spots, I felt like the music could have used a little bit of polish... and then the day turned into night and the music happened to stop at that exact time. And then it started again, but the silence in there was nice (not sure if it was intentional, but it made the music seem better, not worse). It would have been fun if the night actually had different music, maybe some slower piano music: If all the music goes at the same pace, it gets boring after a couple of minutes, and that's less time than it takes me to beat the game.
So I think the music could have been more interesting, but I really like the sound effects (and the possibly unintentional silence that came right when the day was nightening). Good job!
Also, one bug I noticed on Windows: if I walk up to the boat with a package on it and press E, it gives me two options, but if I decide I want to do something else before I do any of them, then I should be able to get rid of the menu. Instead, walking away without selecting an option left the menu on screen, with both options unselectable, and I'm not sure I could use the boat at all after that.