Your color is good, but the pencil sketch is where it's at! The silhouette of your characters is much stronger in the pencil and that's what really got my attention. Visually there's still some room for improvement with your anatomy but the pose is a very strong and dynamic horse pose. Also the light pencil strokes of the lines curving around the horse's muscles and limbs gives a sense of form. All and all, keep up the good work!