Battery
One of the BIG plus points the GB/DS series of handhelds have had is the battery life... Oh dear Nintendo :(
Nintendo has revealed the Japanese launch date for its 3DS gaming console, as well as system specifications, which has prompted disappointment over battery life. Nintendo 3DS Sales for the stereoscopic console will start on February 26 for Y25,000 (£190) a pop in Japan, with the US and Europe set to follow in March. Nintendo …
The problem stems from that the brain's perception of actual distance (and thus proper perception of depth) includes not only parallax (the difference between the two eyeballs' images) but also how the muscles focusing the eye's lens are working. And eye focus while using the device are always focused on the screen at the distance that the screen is, which does NOT necessarily match how the real world is... That training happens at a young age.
a young child's eyes/brain are still getting used to processing real 3d properly and do not really want to be subjected to this fake 3d effect over long periods.
A lot of the stuff we do automatically, ie judging distances based on 3d vision, eyes focusing/aligning correctly, etc. is stuff we essentially learned, over time, during our childhood. The very way this works is by exploiting those learned responses, and could easily interfere with them if they aren't yet fixed.
While the occasional few hours of toy story in a cinema won't do any harm, 5-10 hours a day of it close up would be a different matter.
Nintendo was always going for low-powered devices and tried to get the 3rd party content creators to be more innovative with their techniques. But it seems the market demand for high powered low battery live hand-held game devices has Nintendo changing their paradigm. Look at the iPod and iPod touch, when you're playing games, they don't last long on battery. PSP is pretty much the same which is 3-6 hours. Gotta give the kiddies what they want or their buy from the competition.