I'm surprised that botching the illusion doesn't cost the losing girl her virginity. That feels like an oversight.
To the break the illusion - there's three or so orbs along the back of the stage that you need to shatter. They don't have life bars but you'll hear a sound if you hit them. The problem, is, of course, that you're under attack the entire time and can take out the fake by accident (or get flattened by her combo chain) before breaking every orb.
I'm a little surprised there's no option to increase the health of the fake to reduce the odds of an accidental kill.
Unlocking stage select lets you do actual stage 6 or just straight into one of the Route versions of it.
I fluked the orbs by accident while I was wondering how to go about breaking the illusion. You can hit them using the slide attack and uppercut as Chocolat. The mission only requires the fake not get hit while the orbs are broken, so it's really easy to just run to one side and then go for the orb while the fake slowly ambles over. Her thrust kick is easy to bait and avoid, at normal mode she won't do much more than that provided players keep their distance.
Route D doesn't care if the fake is beaten through force or brains. Only that routes A and B are not entered and players make it to the end (preferably without losing). Both C and D can give the true ending, but I think only D gets the virgin clear sex scene since the prerequisite is to not lose a life at all through the run.
Stage select doesn't allow players to enter routes A, B and C until they've been accessed at least once the normal way. Fortunately, the CG hints tell players exactly what to do for the alternate routes. Players with too many points are better off using stage select + and going directly, albeit at the cost of the storyline. Those who want to do have a clean 0 defeats stat might want this option though.
Still trying to figure out how to complete the stage 4 mission. I'm having an awful time trying to time the slide attack to kick the bombs. As for the stage 6 hidden goblins, I beat one (it's basically an invisible goblin in a grey silhouette) but couldn't find the other.
Farming points: Do a run from the start and make it to the true end route. Save before the final boss during the dialogue scene, repeatedly beat the boss (hopefully as close to perfect as possible) for quick points. A good run with little MP and HP damage nets over 300 points, while perfects can exceed 700.