once you beat the game, the princess gives you the power band weapon, which you need to then beat the game over with, and NEVER PICK UP ANY OTHER WEAPONS. do this and you get the ending, and yes, i know, it' recockulous to have to do such a thing to beat such an already insanely hard game
This annoyed me greatly. I'd played through all the levels enough times after dying over and over on them, i wasn't going to go through the whole thing again as soon as i'd finished the final level. When i finished the final level i deserved at least a "well done" message so i could pat myself on the back.