Here is the full list of all 10 Sakura Agent achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Win a poker game.
Unlock all images in the gallery.
Unlock all of Masumi's and Kimiko's shared scenes.
Fail to stop someone from falling.
Put an end to the invasion.
Unlock all of Kimiko's scenes.
Unlock all of Masumi's scenes.
NEW_ACHIEVEMENT_DESC_1_7
Working hard while patrolling the beach.
Complete your first mission.