Definately needs more shading. Well, either shading, or actually following the limitations of an older console/computer. For instance, the NES can only display 3 colors for every 8x8 tile (plus transparency), so I doubt that was the style you were going for. However, this could be intentional, in which case, you should ignore my criticism.

Though you definately need a bigger preview, whether or not the other criticism applies. As is, it's too small to see properly on the details page.