Hello for a second Pixelation!
Before you call that done a few pointers.
Still not enough contrast. Compare the feet of PPD's edit (top) to yours (bottom):
Right off the bat which 2 colors have more contrast?
His edit also uses less colors, trading that off for more value. 1 is priority over the other on a sprite this size. Notice also how the shadow under the bot creates depth.
Made these top 3 before reading this was a singular boss sprite, bottom 3 after:
Primarily notice the value in contrast, dump them onto different value backgrounds and see how they still read. Not saying you should change the design if it's finalized at this point unless it inspires you, but up the value more. It should be a few quick tweaks.
Also, to touch on something PPD brought up, what's the context of the sprite? Is it a JRPG-style static enemy sprite? Top-down? Sidescroller? Will it be animated? Those are factors that will inform our edits greatly.
