Here is the full list of all 12 Hentai Casual Swap achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Unlock Level 10.
Unlock Level 9.
Unlock Level 8.
Unlock Level 7.
Unlock Level 6.
Unlock Level 5.
Use the help button for the first time.
Unlock Level 4.
Unlock Level 3.
Unlock Level 2.
Visit the gallery for the first time.
Thanks for playing Hentai Casual Swap!