Here are some cheats and tips for the game The Ninja Warriors.
Sound test:
Hold L + R and press Start when the text
“Press Start” begins flashing at the title screen.
Level select:
Hold X + Y, then press A(4), B(4),
A, B, A, B, A, B, A,
B when the text “Press Start” begins flashing
at the title screen. Enter this code again on the level selection
screen to select a specific stage within that level. Alternatively,
hold X + Y and press A, B, A(4),
B(4), A, B, A, B, A,
B, A, B at the title screen.