Orange on coat is because of fire on the right side. Just lighting. Black eyes propably means to be eyes in shadow (anime effect), I'll try to fix the face. Thank you for your post.

My first impression on seeing this piece is that it was an image of a humanoid alien; the pure white skin and large, solidly black eyes made it feel that way to me.  As you mention it is a self-portrait, I suspect this was not your intention.  I wonder if you might be able to find a more suitable skin-tone within the original NES palette or if you might be able to use the shades of grey you have available here to better define facial features.  Note also that, to me, the line I am interpreting as the bridge of the character's nose appears to begin above the eybrow line.

I feel as though the shading on his face could be improved; that both sides of his face are outlined and shaded suggests a little bit of pillow-shading as it seems contrary to the lightsource.  With his head turned a little to his right, I feel like we should be able to see his left ear; it likely could be defined with a little work.

The shading on his body also feels odd to me.  It makes more sense if I see it as being a two-tone jacket he is wearing, with the right side black and the left side orange.  If you intended it to be a solidly orange jacket, I feel the black shading should change to the dark orange.  The orange on the sleeve of his left arm and on his left pant leg feels out of place; they don't seem to work with the lightsource to suggest solidly orange clothing shaded gray in dark areas, instead it feels like oddly-shaped orange patterns on the garmets.

From the hair, face, and lighter outline on the right side of his body, I interpreted the lightsource as being on the left side of this image.  I later realized that, given the lighting on the building and the rocket, the lightsource should be on the right side of the image.

I find it odd that you outlined the right half of his body in gray instead of black.  If his jacket is two-tone and black on that side, I could understand this choice as an attempt to show that the black is being illuminated by the lightsource.  However, I feel it wouldn't light it up in this way and feel that the pant-leg on that side and the exposed side of his raised left arm should also be illuminated on the edge.

The design of the flagpole felt odd to me and, with a quick image-search for a flag-bearer, I found that most (but not all) flags have a ball or decorative piece on top of the pole and have nothing down on the bottom end of the pole.

If the magic coming from his hand would be a lightsource, I would expect the raised palm of his hand to be the lighter colour but it appears darker.

I feel I would like the option to view this image at 1x size in the gallery here; as Pixeljoint's gallery has zoom options built-in, we are still able to zoom in to view it like this so I feel it would be preferable to also have the option to view it at 1x size.  That said, I understand the desire to display it at 2x size as the default and believe it should be up to you to decide how your work is displayed.

Viewing the image at 1x size in paint, I found the two cubic buildings produce a weird flickering effect from the dithering.  It may be due to my monitor but I think it has something to do with an optical illusion; if planning to display this at 1x size, I wonder if you could make some changes to those buildings to eliminate this as it would be rather distracting.

Regarding the color count here, I see it says six colors in the image description but I can see at least eight colors in the image.  Can the color count in the description be corrected?

 Go ahead, it's okay to post it here 

I like the buildings in the background and I like the way the rocket is launched up through the abstractly defined layers in the sky.  If you are open to some constructive criticism on this, let me know and I'll either post it here or do it through PM.