* @return ³ºÅö¤Î¼ö¤¤¤¬°ì¤Ä¤Ç¤â¤¢¤Ã¤¿¾ì¹ç¤Ë¥é¥ó¥À¥à¤ËÁª¤Ð¤ì¤¿ÁõÈ÷ÉʤΥª¥Ö¥¸¥§¥¯¥È¹½Â¤Âλ²¾È¥Ý¥¤¥ó¥¿¤òÊÖ¤¹¡£\n
* ¼ö¤¤¤¬¤Ê¤¤¾ì¹çNULL¤òÊÖ¤¹¡£
*/
* @return ³ºÅö¤Î¼ö¤¤¤¬°ì¤Ä¤Ç¤â¤¢¤Ã¤¿¾ì¹ç¤Ë¥é¥ó¥À¥à¤ËÁª¤Ð¤ì¤¿ÁõÈ÷ÉʤΥª¥Ö¥¸¥§¥¯¥È¹½Â¤Âλ²¾È¥Ý¥¤¥ó¥¿¤òÊÖ¤¹¡£\n
* ¼ö¤¤¤¬¤Ê¤¤¾ì¹çNULL¤òÊÖ¤¹¡£
*/
* Notice the annoying code to handle "pack overflow", which\n
* must come first just in case somebody manages to corrupt\n
* the savefiles by clever use of menu commands or something.\n
* Notice the annoying code to handle "pack overflow", which\n
* must come first just in case somebody manages to corrupt\n
* the savefiles by clever use of menu commands or something.\n
* This function will not exit until the level is completed,\n
* the user dies, or the game is terminated.\n
*/
* This function will not exit until the level is completed,\n
* the user dies, or the game is terminated.\n
*/