Isn't using NPD + Enterbrain + Charttrack/GFK giving Nintendo an unfair advantage?
One of Sony's big advantage in this industry is distribution, they've managed to sell much better in markets Nintendo has difficulty with, many of those wouldn't be tracked at all, they only turn up in shipment figures and are estimated by others.
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.