Adding stereoscopic 3D graphics to classic titles for the Nintendo 3DS' "3D Classics" series is not as simple a process as it might seem, according to the developers responsible for the ports.In a new Iwata Asks conversation , Nintendo special planning & development department employee Takao Nakano recalls some of the problems that caused development on the 3D Classics version of top-down space shooterto take roughly 20 times as long as a normal port.Elements that made visual sense in the 2D original game -- like bombs that hit the ground immediately when fired -- caused "all sorts of discrepancies" once the player's ship was shown floating above the ground in the 3D version, Nakano said.Adding a short interval between firing and impact fixed the visual problem, but ended up altering the classicgameplay slightly, he pointed out. "It was a big challenge making something that would satisfy fans of the original and provide a fresh surprise on the Nintendo 3DS system," Nakano said.The team also ran into trouble porting NES/Famicom classicto a stereoscopic view, finding that adding new 3D collision detection for the ball and racket would "[take] as much work as making a tennis game from scratch," Nakano said. The port was eventually scrapped.Elsewhere in the interview, Nintendo software development & design employee Kenta Tanaka talked about his efforts to make 3DS eShop versions of classic Game Boy titles as authentic as possible, adding effects like a green tinted background and old LCD-style "ghosting" afterimages for moving sprites."I even recreated the way the red LED on the left-hand side of the screen cover would grow a little faint when the power started running low," Tanaka pointed out. "I don't know if anyone will like that, but I paid attention to that as well."