In North American Club Nintendo members will net extra coins for downloading the digital version of New Super Mario Bros. 2, but Japanese fans get an even sweeter bonus: An entire game. Specifically, Japanese downloaders will get Donkey Kong: Original Edition, which features a factory level not found in the original NES release (pictured).
As Wired notes, Donkey Kong: Original Edition has never been sold, though it was included as a pre-installed Virtual Console game on the Mario 25th Anniversary Red Wii bundle in Europe.