They look a little too...random...to me. It look like you just randomly threw pixels onto them. I don't like them too much. I suggest less clutter on them and more a smoothing transition.
@worldpeace - That is one of the best puzzle-type levels I've seen. I love everything about it. That is a great way to use a Wiggler (guarding a pipe). I also love the Bullet Bill/Throw Block maze. Are those gray castle block ExGFX available somewhere? I like them a lot. (They look like SMB1 Castle bricks). I agree, though, that the fish could be better - maybe make an ExGFX change to their graphics to make a "new" enemy. An SMB2 Beezo would work pretty well.
[?] Miscellaneous Helpful Hints
If I moderated your hack, there was apparently a 90 percent chance it was rejected.