NES Version

  The trick to getting the correct (aka second) ending is: in level 99 a crystal ball will appear very quickly near the upper left of
 the stage, if you get that a secret door will appear in that open area in the middle of the stage. You must go through that door to
  get to the correct ending/boss. Once through that door there will be 12 special levels before reaching 112 (the true ending),
                           those levels are labeled A0-9 and B0-2...then the boss.

                                       Stage Select passwords:
                                         DDFFI (untested)
                    EECJJ - use the one or two player continue option to select level 1 to 112

                                        Final (correct) Boss:
                                             EECFG