Mini-game:
     At the main menu, highlight the "Options" selection and press A +
X to start a mini-game.

Multiple endings:
     There  are  a  total of three ending in the game. One if you save
all  friends,  another  for  saving  just  one friend, and a third for
saving no friends.

Eriko in her underwear:
     Start  a  game  and  do  not  rescue anyone. Eriko will lose more
clothing  with  each lost friend. By the time you reach Level 6, Eriko
should be in nothing but her underwear.