Here is the full list of all 29 Dark Nights achievements.
Not that easy
Kurato's romantic end
Are you curious about his brother?
Reward for studying well
Death end 6
Such an aggressive MC
Death end 7
Sachiro's normal ending
Not the usual choice
Sachiro's romantic ending
Holy umbrellas
This is a horror VN
Zeikun's romantic ending
Death end 4
Zeikun's normal ending
Good job guessing!
Death end 8
Kurato's normal end
He is coming
Going for both, I see
The bed is safe, right?
Death end 2
Junoru's romantic ending
Death end 1
Peaceful passing
Written by the author
Mask it off
The opening theme piano version
Death end 3