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