A demo is like a sample sachet of shampoo. A piece of sausage a lady at a supermarket offers you. It's a small, free thing, designed to lure you into buying a product. It is not, and never should be, a product itself.
Yet Capcom is testing the waters in Japan with a paid demo of Nazo Waku Yakata. The innovative title, which uses none of the 3DS' buttons (instead relying mostly on sound and the mic), has its first chapter up for sale on Nintendo's eShop for ¥200.
Now, granted, that only equates to around USD$2.50. It's not busting anyone's balls. But it's the principle of the thing. Capcom isn't calling it a demo, but as a small offering of a full, standalone retail product that went on sale this week, that's exactly what it is.