SD Hiryu no Ken

Sound test:
Press Up(2), Down, A(3), Start at the title screen. The main menu will appear. Highlight "Story Mode" option, then hold Select and press Start.

Sprite viewer:
Press Up(2), Down, A(3), Start at the title screen. The main menu will appear. Enter the "Options" menu.

Hidden speed option:
Enable the "Sound test" code. Enter the "Sound Test" menu, then press Start to display the character selection screen. Choose a character, then hold Select before the fight begins. If done correctly, you will be able to select a hidden third speed option.

Player modifier:
Press X at the Vs. mode character selection screen to switch player two to a CPU controlled character. Press X again to switch both players to CPU controlled characters. Press X a third time to return to normal.

Hint: Easy Story mode:
Enter Vs. mode and select the character that you would like to play through in the Story mode easily. Select any character for player two. Set the handicap all the way to the right to give player one full advantage. Win the fight, then select "Exit" to return to the main menu. Select Story mode and select the character that you used in Vs mode. If done correctly, that character will still have a large advantage with weaker enemies.