Classic mode
Enter the "Marathon" option at the main menu, then hold [L] and press [Select]. Enter the Marathon screen and select the "Popular" option to play the classic version of Tetris. Note: [L] and [R] will move the piece left and right.
No music
When you go to the screen after you select "Popular mode" but before you actually start playing, press [L] + [R] + [A]. You will enter the original game without the music, but you still have sound effects. Note: When the game ends, the screen freezes requiring the Game Boy Advance to be turned off.
Control starting screen
At the main screen, you will see a "universe" spinning. Hold [R] to make it spin very fast. Hold [L] to make it stop, then rotate in the opposite direction.