That is very much incorrect. It's as impossible to make a "perfect" piece of art as it is to teach a pile of rabid hedgehogs to tango.
Zeid washed out the colors on it, so the highlights are too big now, and much of the form is lost, the beard could be much improved with something better than a quick and easy dither, maybe actually draw in the curly hair? The shading, while not that bad, it not coming from any specific direction, there are no cast shadows, the anatomy is lacking in detail, the eyepatch's cord should probably not be a straight line, the side of the head and ear area is a bit confusing, the hands are messy, the pockets looks strange, more detail could be added to the pants, like laces and seams. I'm only getting started, and that doesn't even begin to cover stylistic choices and who knows what else.
But anyway, just do the best you can, and don't ever think you'll be able to make something that is "perfect."