indeed, it doesn't. but main problem is that one of the golden rules of pixel art is the complete control over each pixel, both placement and color. and, as you state, the color choice in this piece wasn't really created by your hand. and that's quite despicable as it tends to increase the color count to execise limits, and often unnecesary. as you can see in the sample i made of your palette, for example 1/3 of the colors are a bunch of grays that are practically invisible unless you zoom the image to at least 4x. a wise color choice will not only look nice to your fellow pixelers, but also provides a good exercise to understand colors in their nature, and that's a very powerful tool that can be ported to any other art form. not to mention that you'll find more satisfaction in a piece made all by you.

in this case, I've quickly picked the colors that are really relevant in the image, reducing the number of colors from 98 to a more reasonable 16 (15+transparency). I strongly encourage you to try to use these colors either as a guide or directly using as your palette, and redo this, and of course resubmit it.

so this is basically a non-pixel art piece, and will hardly get aproved due this.

I see, so that's the problem ... I think the reason why I used that many colors is because I often reduced the opacity of the pencil down to several percent, and after that I just used it to to create such gradient effect. So when the pencil came into contact with other existing colors, it will create a new color. Why did I do such thing? Dunno, just trying to implement new techniques I guess...hell, it doesn't hurt though.

98 colors? why 98 colors? it does not make any sense. there's a lot of unwisely positioned colors that do resemble a lot a color reduction. even if you made it all by hand, the abuse of the color palette is just ridiculous.

Huh? what do you mean by that?

I'll hold off on the voting until we hear more from the artist about this piece.

Looks like a color and size reduce of a mech manga scene