Nintendo has announced that some DSiWare titles will not be transferable to the 3DS system, but they offered absolutely no explanation as to why.
A list of games that will not be making the cut was released, one of which was Earthworm Jim. Some of the other non-transferable games are Oregon Trail, Sudoku Master, and Real Soccer 2009 and 2010.
Aside from those, however, are all the games available in the 3DS' eShop which will go up some time next week. Players will have access to some classic Game Boy titles, 3D takes on old games, web browser, 3DSWare and any DSiWare titles from a previous device.