Why there is revision needed on my pixel-art? It's not plagiarism, it's my friends dog ;-;
https://www.dropbox.com/s/qycj1lb5scn99xu/pieselek.png?dl=0
http://pixeljoint.com/pixelart/100348.htm
I worked 7 days just to end this, I dont think that's need revision.

Was a reason given?
My guess is that your pixel technique feels... off. Your clusters look like something you'd get from tracing a photo (automatically or by hand) without considering what you're drawing - and yet in other areas, you made some great choices. Your dithering is also very strange - you have some oddly sharp transitions, and at times you go from one pair of dithering colours to the next, without using the solid colours which would create a better transition.
In some areas around edges it also looks like you just didn't put in the pixel-level care that's evident around the eyes.

All in all, this just gives the impression of something not entirely hand-made, with the odd choices you made.

I used a lot of dithering because i wanted to make fur-effect, it's didnt worked well ;-;