Level Select & Debug Mode
Press Up, Up, Down, Down, Up, Up, Up, Up at the title screen. These codes and trying the "Game Genie" cheat code or scroll "Down" to select the "Sound Test".
Sound Test Codes
After the scrolling down to select the "Sound Test" and enter the following:
- All Emeralds: 02, 04, 05 and 06
- Eighth Special Stage: 07