I've noticed some of your images are poorly formatted. The Toon Link has WAY too much white space on the right, and possibly not enough on the left. I also noticed stray pixels on the right of Toon Link (I really can't stand stray pixels). I also feel that the quality of some of the sprites, especially the pixel ones, are blurry.
As for the artwork itself, you have stray lines all over. It looks as if you were in a hurry to draw these, and didn't take the time to clean up the image. The colors are rough around the outline, as well. I like the shading on the Toon Link, but spend more time polishing!