@DPBOX: Looks like someone is making a My Little Pony hack. The style is properly nailed, especially in the clouds and bushes, color, and shading. The arrangement of the flowers does reveal the grid-like nature of the overworld though and to offset this, I would consider adding tiles that would let you "overlap" flowers, trees, and bushes so that you can cluster these props with more variable density and make it seem more natural. I am not sure how I feel about leaving the bottom and left as evenly mixed as they are: it has potential to host what is definitively a forest, a flower field, and a plain if the details are less blended, distinguishing these pieces of (presumably) Equestria and giving more suggestion to the sort of level you will enter. I would also do something about the very angular shore line and lack of sand-to-water/grass transitions. The space alloted to the wheat fields on the right also seems large. If less spread-out, you can expand the mountains inland just enough to not shove Mario and the levels into the perimeter where they are close to or hidden by the overworld border. The longer and straighter mountain edges would look good with some angles worked into them.

I am wondering about the forest at the bottom, as it carries connotations of a crossover between these universes.