That's actually more than a "Couple", but now you can at least see what we mean by the quality of the overworld sprites. We would like it if you could tell us what is going wrong with the sprites or deliver a few pointers. I believe the problem is in the shading, which is why they don't match up with the other sprites.
If you would like some of the drawings from where they are based off of, I will gladly give them to you. Some of them are half-finished, so I might end up completing or re-drawing them should you ask.