http://www.planetgamecube.com/news.cfm?action=item&id=6714
Each of the six modes of play features a theme based on a classic Nintendo game, such as Super Mario Bros.(R), The Legend of Zelda(R) or Metroid(R). The traditional Tetriminos (falling blocks) and line-clearing strategy remain the staples of the game, but the touch screen adds a new element of interactivity.
Some modes give players special Tetris puzzles to solve. Others feature head-to-head action between two players, or massive wireless battles between 10 DS users, even if only one player has a game card. Players also can log onto Nintendo Wi-Fi Connection to compete in two- or four-player battles. Tetris DS even includes a point-based rating system based on players' battle results. Opponents can see one another's ratings, which indicate their skill levels.