Glad you're enjoying the games so far!
The ending with the scene is a dead-end, yes. There will be another once I finish up the slut mode content. As for the fight itself, which hypno-immunity item? The good luck charm won't help with him, you need another. If you ARE using the one specifically for him, defeating him shouldn't be that difficult. Keep in mind that it's a multi-use item, and you have to re-up as the fight goes on.