Level select:
Enter the sound test menu. Set the "Music" option to "Continue", "FX" to "Appear", and "Speech" to "Think". Highlight the "Exit" option and hold Left for approximately five seconds. A sound will confirm correct code entry. A level select menu will appear when game play is started.

Unlimited lives:
Hold A + B + C + Right at the Sega logo. Continue to hold those buttons and press Start when prompted. Release the buttons when level 1 begins. An infinity symbol will replace the number of lives to confirm correct code entry.