Post the 90x90 tiles, we can't really comment on scaled down art, as it hides technique. I can tell that the grass is pillow shaded (there's no light source, the color just becomes brighter towards the middle of a leaf). I like the sea colors and the beach rocks (I'm a sucker for tinted grays). The whole piece has a sunny feel to it, which is good, though maybe the greens are a bit too dark and could use some yellow introduced into them.
So yeah, show us the full tiles and maybe explain why you are scaling them down.