Chain meter:
During game play, press Z to display a chain meter under the chain status.

Additional credits:
Collect at least three or four hours of total game play to get additional 
credits. After collecting six hours, you should have about nine credits from 
the start, but it is not 
unlimited.

Gallery 1 option:
Successfully complete trial mode without using any continues to unlock the 
"Gallery 1" option at the "Appendix" menu. Alternately, accumulate at least 
five hours of total game play.

Gallery 2 option:
Successfully complete the game under any difficulty setting to unlock the 
"Gallery 2" option at the "Appendix" menu. Alternately, accumulate at least 
ten hours of total game play.

Sound test option:
Successfully complete the game under the easy difficulty setting without 
using any continues to unlock the "Sound Test" option at the "Appendix" menu. 
Alternately, accumulate at least fifteen hours of total game play.

Game mode option:
Successfully complete the game under the normal difficulty setting without 
using any continues to unlock the "Game Mode" option at the "Appendix" menu. 
Alternately, accumulate at least twenty hours of total game play.