Hey
Try to reduce amount of colors. Use pallettes. I think you could make it with only 8 colors - you have 42 colors now! (You can use wouterpleizier.nl/pj/ to see if some colours are not needed - PJ Image Specs tool)
Shading and general feeling is very nice. Also, additional white outline is not really necessary (IMHO) Welcome to PixelJoint! :)
hello! I really appreciate your feedback. That website seems very helpful. Thank you. I will try my hardest to do better!