Here is the full list of all 18 Hentai Zodiac Puzzle achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Unlock all achievements
Open the first girl
Open the second girl
Open the third girl
Open the fourth girl
Open the fifth girl
Open the sixth girl
Open the seventh girl
Open the eighth girl
Open the ninth girl
Open the tenth girl
Open the eleventh girl
Open the twelfth girl
Use random choice
Click on a wrong spot
Find the first difference
Use hint
Don't use hints