Zelda II-esque tileset! Suggestions?

I...really ran out of creativity halfway on this one. :v It's supposed to be an homage to Zelda II, the abused and neglected stepchild of the Zelda franchise (not saying I ever played it, myself) but with the typical Knytt Stories feel.

Suggestions? I've been wrestling with the idea of giving the ground a solid black (or near-black) outline, rather than the shaded outline, as much as I do like the way it looks. I'd just hate for the tileset to clash with other tilesets, when it's used in an actual level. :T I've always hated it when in a level, I go from a generic, Knytt-esque looking tileset to something suddenly hyperrealistic, with thousands of colors.

Another thing I've been thinking of is changing the bridge. I wanted to make it look like the bridges in Zelda II, but I think a flatter bridge might look better.

I actually think both the ground blocks and the bridge look pretty great! What's the black stuff supposed to be?

I actually think both the ground blocks and the bridge look pretty great! What's the black stuff supposed to be?

Background bricks! I can throw up an example screenshot, if you want.

EDIT: Uploaded an example screenshot!
EDIT AGAIN: Oh, something I should probably mention, the palette I'm using is in the upper-left corner of the blank box. And, uhm...ignore that white square, dunno what happened there, heh.