Oh boy -- get ready for years of competing studies and hysterical news reports claiming that 3D is either life-threateningly dangerous or perfectly safe. (Cellphone radiation, take a backseat.) Today's delightful round of panic comes courtesy of Nintendo's Japanese warning guidelines for the 3DS: players are advised that 3D gameplay causes eye fatigue more quickly than 2D gaming and are told to take a break after 30 minutes of play -- and you should quit immediately if you get ill, which makes sense. Nintendo also says that children under six shouldn't use the 3D mode at all, since their eyes are still developing, and that parents can use controls built into the 3DS to lock it into 2D mode for children.