This is nicely done. As an aside, there was something posted a while back regarding some of the custom workstations that were used to produce art for NES games. One thing I never really considered, but learned from that article, is how artists back then utilized the imperfections of 'pixels' on a TV set to give sprites more richness. In many ways viewing pixel art on a perfect modern display loses something – a kind of 'warmth' or complexity that becomes too 'perfect' on a high-def display.