Here is the full list of all 100 Hentai Hexa Mosaic achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Girlevel I - Start
Girlevel I - Success!
Girlevel II - Start
Girlevel II - Success!
Girlevel III - Start
Girlevel III - Success!
Girlevel IV - Start
Girlevel IV - Success!
Girlevel V - Start
Girlevel V - Success!
Girlevel VI - Start
Girlevel VI - Success!
Girlevel VII - Start
Girlevel VII - Success!
Girlevel VIII - Start
Girlevel VIII - Success!
Girlevel IX - Start
Girlevel IX - Success!
Girlevel X - Start
Girlevel X - Success!