Very colorful!

Well, you certainly have quite the variety of ground detailing. I have to admit, I don't like to use random patches of dirt/sand/grass/fluff because it gives away the 16x16-tiled nature of the engine when pitted against things that should have a much more natural flow. And yet, despite that, the way you consistently spread and combine them, as well as the variety of tiles you use, actually looks quite good to me. If nothing else, it's that consistency that sells me, not just on a screen-per-screen basis, but the way you carry it though summer grounds, winter peaks, fiery caves and swampy marshlands.

Perhaps the one thing I might consider is the usage of those Zelda 2-styled stone pillars. On an overhead view, the point comes when their height causes them to look like they're laying across the ground rather than reaching upward. Of course, if you use layers so the player can move around behind them, it would help to negate this effect.

Very interesting tileset. I like it!