Unlock Movie viewer and Sound test:
     Beat the game on Normal to unlock the Movie viewer and Sound test
options.

Belly Slam:
     Press Jump/Attack as Benkei and you'll do a belly slam.

Unlock Sount test and Movie Viewer option:
     Finish  the  game  on  the  normal  difficulty level to
access to the sound test and the movie viewer options in the
Extras option.