Tetris DS (Nintendo)
Developer: Nintendo SPD
This game has unused graphics.
Nintendo's two-screen rendition of Tetris, themed after classic NES games. It introduces plenty of new modes, too, like Catch and Puzzle.
Are there any other remnants of this mode? Was it seen in any pre-release material? Is it in the Japanese version?
Alongside the menu options for all of the other main modes, there is an extra one which goes unused. It would have been themed around Ice Climber, a game which is otherwise only prominently referenced in level 15 of Marathon mode. The name seems to translate to "Niagara," as in the waterfall. In the English version of the game, the text remains untranslated.
An unused play field graphic.
A Super Mario Bros. flagpole and end-of-world castle against a black background. In Classic mode, Mario at the top of the screen never makes it to the end of a level, making this go unused.
NES Game Leftovers
Mario and Luigi's death sprites from Mario Bros., who are otherwise only seen on the title screen.
On the bottom screen of Puzzle mode (themed after Yoshi's Cookie), Yoshi is seen looking to the left. However, it turns out that the image itself has Yoshi looking to the right. The game puts a separate graphic over his eyes to make him look the other direction.