Here is the full list of all 39 Gal*Gun: Double Peace achievements.
Unlock All Trophies
Complete Profiles for Every Girl
Obtain All Images in the Gallery
View All of the True Endings
View the True Love Route's True Ending
View Patako's True Ending
Receive a “Perfect!” Score VS Patako
View Kurona's True Ending
Receive a “Perfect!” Score VS Kurona
Defeat 100 Demon Girls
Receive a “Perfect!” Score VS Ekoro
View Ekoro's True Ending
Collect All of the Panties From the Changing Room
View Sisters Route's True Ending
Receive a “Perfect!” Score VS Shinobu & Maya
Get a Perfect Score on “Demon-Attracting Balm”
Get a Perfect Score on “Sisters' Odd Ritual”
Achieve Godlike Rank
View Maya's True Ending
Receive a “Perfect!” Score VS Maya
Receive a “Perfect!” Score VS Mr. Demon Balloon
Get a Perfect Score on “Maya's Medical Care”
Get a Perfect Score on “Maya's Demon Calling”
View Shinobu's True Ending
View Your First Ending
Experience Your First Final Doki-Doki Mode
Receive a “Perfect!” Score VS Shinobu
Receive a “Perfect!” Score VS Mr. Demon Veggie
Get a 30 Combo of Ecstasy Shots
Make 50+ Girls Experience “Double Peace”
Give 500 Girls Euphoria
View Aoi's Ending
Fulfill 10 of the Girls' Requests
Get a Perfect Score on “Her Majesty Shinobu”
Get a Perfect Score on “Shinobu in the Window”
Fire 1000 Pheromone Shots
Get 100 Ecstasy Shots
Experience Your First Doki-Doki Mode
Give a Girl Euphoria