Here is the full list of all 16 FREE GIRLS! achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Girl 5 gallery
Girl 5 level
Girl 5 select
Girl 4 gallery
Girl 4 level
Girl 4 select
Girl 3 gallery
Girl 3 level
Girl 3 select
Girl 2 gallery
Girl 2 level
Girl 2 select
Girl 1 gallery
Girl 1 level
Girl 1 select
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