Regarding the theme, so far, this is my favourite track. It truely truely feels at home with the game and the beach area, its smooth calm happy visual and colourful, never too much, catchy - congratulations.
Your mix is nicely balanced and levelled, I've got nothing to say except maybe some more love for the low ends, a bassy instrument or so, that feels like an empty space that could be filled.
Compared to some other tracks, I haven't got much to say, because it really truly feels like this song fits the theme WELL. It's exactly what I had in mind when I pictured the theme's vibe. Bravo !