Here is the full list of all 69 Hentai Secrets achievements. It takes around 0-1 hour to unlock all of the achievements.
Complete level 13
Complete level 14
Complete level 12
Complete level 11
Complete level 10
Complete level 9
Complete level 8
Complete level 7
Complete level 5
Complete level 6
Complete level 3
Complete level 4
Complete level 1
Complete level 2