Okay, I'm going to start with the stuff I believe needs to be improved.
The skin appears to be flat, as there is no shading upon it. This is also true with the eyes, which look slightly unrealistic, with the combination of the black outlines around the eyes, and the lack of pupils. Here's some tutorials for these: [link][link]
I like the hair though, and believe it is very well executed. Also, the ears are very well done, and as is the clothing, which helps achieve a realistic look and feel to the rest of the pixel.
I like this, but the bad points are distracting, but I hope to see plenty of improvement in the future
I feel the style is how the artist envisions it to be. The style is not totally realistic and in my opinion made to look super deformed (aka chibi-esque) and they pulled it off really well. now if they were going for realistic it's a little off, but my opinion of the overall impact is really appealing and cute. the facial features are well done and everything else is wonderfully done. This is a great work in my opinion, keep up the good work. I would just suggest to look into chibi characters a little more and do your research.