Here is the full list of all 100 Girls of Hentai Mosaic achievements.
Without underwear, <3
Without a bra
Without outerwear
Undressed!
Marise unlocked in the Gallery
Text smile 15
Text smile 16
Marise, 22
Outerwear
Manami unlocked in the Gallery
Text smile 14
Manami, 19
Kichi unlocked in the Gallery
Text smile 13
Kichi, 24
Hotaru unlocked in the Gallery
Text smile 11
Text smile 12
Hotaru, 24
Text smile 10
Aneko unlocked in the Gallery
Aneko, 24
Yoshi unlocked in the Gallery
Text smile 9
Yoshi, 24
Yachi unlocked in the Gallery
Text smile 7
Text smile 8
Yachi, 24
Yasu unlocked in the Gallery
Text smile 6
Yasu, 20
Text smile 5
Tsuyu unlocked in the Gallery
Tsuyu, 18
Tama unlocked in the Gallery
Text smile 3
Text smile 4
Tama, 20
Suzume unlocked in the Gallery
Text smile 2
Suzume, 21
Riko unlocked in the Gallery
Text smile 1
Riko, 19