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.
Fail to stop someone from falling.
Unlock all of Masumi's and Kimiko's shared scenes.
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.