I think your main character sprites could use a little more contrast and saturation, and you could also cut a few surplus colors for cleaner images and easier animating.
with the new colors he pops out a little more, and looks more 3d.
as for the flan, it's probably supposed to be disgusting looking and slimy so I didn't do much to make the colors look pleasing to the eye, but I did cut it down to four body colors, as it had waaaaaay too many hues, most of which weren't even distinguishable from one another to the naked eye.