Love the details and the realism. If I were spike I'd be a bit more gentlemanly and also have my weapon (more likely a sword/bow) and shield at the ready and leaping between her and whatever threatens her.
Spike looks badass. ^^ Great job there. Twilight...you either have problems drawing horses, or you had trouble mixing a realistic horse with the neccessary Twilight characteristics. She just looks a little strange.