Ghouls 'n Ghosts - Random bug

To perform this bug you've got to have a spell cast on you so you're turned in to the old man. Then jump, shoot and turn around at the edge to get stuck on top of the edge. Now quickly jump to the left to stay on the platform. If you've died after reaching the checkpoint you'll notice an invisible wall here stopping you from going backwards in the level. Similar glitches can be performed in other areas as well. If anyone wonders I've beat the game without an emulator or save-states. Yes, even the second-playthrough you have to do.