This is an awesome game! I actually have always liked erotic horror/survival but there weren't too many options out there. I know you have probably been bombarded with suggestions, but if you were still looking for ideas, I would enjoy there being some kind of hospital or haunted house style level (Thinking something like Silent Hill maybe). Ghosts, Nurses, and Mannequins would be cool enemies. Really love the more brutal ones like the zombie grabbers and Jenny (might have mixed up the name). Also like the idea of like a captive enemy style galley that a person just below.
Of course feel free to do whatever you want, the game is already in a good position and as far as I can see it is worth the money (Just thought about while writing this, but an old gods/Cthulhu like map might be also really fun)