The sand, purple, and metal sets look very good. I'd have to see the psychedelic in practice; personally I always hated that set and just use clear physics when it comes up. I'm not sure how I feel about the one way arrows you're using in metal though - I'd have to see how they look animated, but they're a bit hard to read in the screenshots.
I do not like the tree set. The main issue you have is that your dirt pieces don't combine to form larger pieces well. Ideally, if I take organic-looking pieces like those dirt chunks and use a lot of them to form a larger chunk of terrain, it should be hard to identify where the boundaries of the component pieces are. The way you've shaded these pieces, it's very difficult to conceal those boundaries. If I wanted to, I could take that sample level you have and draw lines where the edges of each dirt piece are.
EDIT: The rest of the tree set is good. The tree leaves especially work well; the shading works to show individual bunches of leaves within the structure of an overall tree. Find a way to make that dirt tile better and it should be fine.