Bloody Pause Screen
Wait a few moments at the pause screen, and ghosts will begin putting bloody handprints on the screen.

Ending bonuses:
Successfully complete the game to unlock the "Battle Mode", "Ghost List", "Sound Test", and "Special Function" options as well as alternate costumes.

Alternate ending:
Successfully complete the game under the nightmare difficulty setting. Note: You must play from beginning to end.

Chapter select:
Successfully complete the game under the nightmare difficulty setting. A "Chapter" option will be unlocked in story mode.

Nightmare mode:
Successfully complete the game in battle mode