BEFORE THIS MOVIE SAW THE LIGHT OF DAY....
Disney was known for it's family oriented films. Even the well-known Disney classics (SNOW WHITE, CINDERELLA, FANTASYIA) had a dark side to the villain, but never as dark and gothic as THE BLACK HOLE. The story was intense, and the special effect was incredible (for the time it was released). The ending could be changed to be a little less christian-like (Maximillion and Hans Rienhart merge to be placed above what looks like hell, while the good guys pass though what looks like heaven's gates with an angel leading the way).
Perhaps a remake, with Tim Burton or Guillermo Del Toro directing?