After beating the last boss, if the hundreds number in your highest score is one of the following denominations, a different character will appear at the start of the credits. *Note: this will only appear by beating the game in Round/Loop 2 or above.
While playing, pause the game and press the following buttons:
At the Options Menu #1, press the following buttons:*Note: The Round and Stage Select cheats have to be entered in Option Menu #1, but they will appear in Option Menu #2.