Between these two, I just see dithering added, and lower saturation in the second. Honestly, you really do need to add significantly more contrast. This means the difference between the lightest values and the darkest values. Make this difference greater, and not only will the sprite come out less fuzzy and undefined, but the lighting will also be more apparent and make more sense, as well as the dithering being of much more use, as currently the lightness of the colours are very close.