Notice how it dropped like a rock with the US market (steeper, actually; it outpaced even some financial stocks) and rose based strictly on a socialist US bailout rumor?
Truly strong stocks dropped less, if at all, during the turmoil. Look at how some of the biotechs and established stocks like IBM have held up. Why do you think Nintendo is so volatile compared to them, when the macro worries have nothing to do with their core business?
NTDOY blows with the wind and has no strength of its own. It has no driving events in the future, being solidly in the middle of cycles for both portable and console. It has nothing to push it upward and won't for years to come.