Just finished this great game. Had a problem with the sex chamber walkthrough. My problem was: The fourth girl, Lotti, to open her, you need to reach ten cumshots. Well no - actually. You need to Bukkake shots on of the girls with more than four hearts when you have 10 vitamins in your inventory. 10 blowjobs does not count (That pissed me of as I tried this for at least an hour or two - then revelation). You need to "Play" with one of the girls (For me, at the final gathering place before everyone leaves), have at least 10 vitamins, and then when in the room, select the vitamin icon and there you have it 10 facial spurts, which fullfills the requirement. Just for fun I did 10 for each of the four girls.
Great ending as an into to Treasure of Nadia. Kinda sucks you in - gorgeous graphics and another hot Nun/Sister.
Also Big Cheers (Beers) to the game walkthrough dude - made the whole thing bearable.