Here is the full list of all 24 Dark Fantasy: Epic Jigsaw Puzzle achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Complete Portrait-1
Complete Portrait-2
Complete Portrait-3
Complete Portrait-4
Complete Portrait-5
Complete Portrait-6
Complete Portrait-7
Complete Portrait-8
Complete Portrait-9
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Complete Portrait-12
Complete Portrait-13
Complete Portrait-14
Complete Portrait-15
Complete Portrait-16
Complete Portrait-17
Complete Portrait-18
Complete Portrait-19
Complete Portrait-20
Complete Portrait-21
Complete Portrait-22
Complete Portrait-23
Complete Portrait-24