The ability to download full retail games on 3DS hasn't gone down too well with Mario fans in Japan, nearly all of whom chose to grab his new quest via traditional retail outlets. Nintendo boss Satoru Iwata has told Wall Street Journal (thanks Joystiq) that just five per cent of sales in Japan were downloads.Japan's other digital offering, Brain Age sequel Demon Training, faired better with 20 per cent digital sales. Iwata suggested that a greater portion of people bought Brain Age digitally because of the convenience of playing the mini games daily without having to carry/swap cartridges. The CEO called initial digital sales "a good reaction" to the new initiative. Considering the £39.99 price (£10 over a boxed copy) that UK customers must pay for the download version of New Super Mario Bros. 2, we can't see its digi-sales going down to well in the region either.