Here is the full list of all 15 Hentai Babes - there are In Costume achievements.
Finish fifteenth puzzle
Finish first puzzle
Finish second puzzle
Finish third puzzle
Finish fourth puzzle
Finish fifth puzzle
Finish sixth puzzle
Finish seventh puzzle
Finish eighth puzzle
Finish ninth puzzle
Finish tenth puzzle
Finish eleventh puzzle
Finish twelfth puzzle
Finish thirteenth puzzle
Finish fourteenth puzzle