Whoa, lots of stuff. You've probably done more Graal-related art then me, as well it looks like you have a general understanding of sprites. I'm not all happy about the general quality of the images.
General things about your images:
1. Lack of AA. Ya, pretty jagged stuff.
2. Contrast. Lots of your stuff really just looks like colors thrown together, without consideration of contour and the such.
3. Horrible palettes. I myself prefer dusty, monotone palettes for work. My opinion, but I do enjoy other vibrant ones. Yours just seems pretty default, and it looks like you didn't spend much time mixing colors.
I give this link to everyone;
http://www.natomic.com/hosted/marks/mpat/shading.html
Should help you out some.

Good luck, and keep at it. You've put lots of work into creating that much, but you need to spend some more time on quality.
Edit: About the GIF and PNG thing. Gifs were made illegal because of the whole patent thing. As far as I know, that Patent expired and you are now allowed to use GIFs. However, PNGs and MNGs are superior anyways. No point in using GIFs.