Mario again

[Ninspriterx]

You can cut down on a few colors. I will tell you to start off with the red. You have 5 shades, yikes.
Okay 1 through 5 being darkest to lightest. Get rid of 5. If you want a light color to AA the white of the M logo you can actually use one of the light skin shades (it's what I do it I ever do that.) Get rid of 3 and make 2 a bit lighter. Like a 2.5, that'll help.
With such a small sprite many colors do seem quite unnecessary.

You have a good shape going on. The arm has weird shading. I like the way you shaded the arm in earlier sprites, where it's mainly the main color and the darker shades just AA the lines and maybe a true shadow here or there.

Also the shoes seem awkward. I also like the shoes in the earlier attempts. I would suggest using that style, but don't add up on the legs to maintain current height when adding more. Work down and add more from the bottom.

And there's lots of other things like corrective skin highlights and just the way things are shaded that I would approach differently. For now this is all I know how to explain, I hope it helps.