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.
Fail to stop someone from falling.
Unlock all of Masumi's and Kimiko's shared scenes.
Win a poker game.
Unlock all images in the gallery.
Put an end to the invasion.
Unlock all of Kimiko's scenes.
Unlock all of Masumi's scenes.
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Working hard while patrolling the beach.
Complete your first mission.