Nice looking piece but..
Pillow Shading KILLS this piece, you should try using another way of shading for this one.
Dithering in MSPaint isn't hard, it just takes a lot of time, and Time is an essential factor when doing Pixel art.
I see some of your other pieces uses a proper way of shading, and there's no reason that this won't shouldn't. I see potential, you just need to keep working on it