3D Altered Beast Hidden options
At the title screen, hold B and press X to unlock an “Options” menu that allows you to change the starting level, difficulty, health, and amount of lives.
Beast selection
At the title screen, hold Y + B + A + Down/Left and press X to unlock all beasts.
Continue from last played level
When changing the starting level with the “Options” code, hold Y and press X.
Sound test
At the title screen, hold Y + A + Up/Right and press X.