Wow! Those pixel Scars are amazing!
As for feedback, the shading and detail is excellent, however, if I was you I'd adjust the outline colour of the muzzle as it isn't as clearly defined as the main body colour, but other than that I'd say it is fantastic!!!
If you ever wanted some more practise, could you do a pixel Chimalsi? http://lionobsession.deviantart.com/...-Ref-470350723
It would help with mane styles!

I can't wait to see more!