Here is the full list of all 27 Dreamwalker: Never Fall Asleep achievements.
Find 32 Dreamer's Sheep.
Release Sandra from the Nightmare.
Finish any Hidden Object Puzzle in less than 30 seconds.
Complete all Hidden Object Puzzles without using a hint.
Collect all Postcards and Stamps.
Finish all Minigames without skipping.
Finish all Meditation Minigames without skipping.
Record the murderer's confession.
Get to Allan's atelier.
Find the hard evidence.
Complete 3 Hidden Object Puzzles with no more than 5 mistakes in each one.
Escape the prison cell.
Break into the mayor's cabinet.
Find 16 Dreamer's Sheep.
Read all the notes placed throughout the game.
Find the book about the Nightmare.
Find 3 Hidden Objects in 3 seconds.
Save Hellen from the car wreckage.
Escape the carriage.
Watch all the cutscenes from the first hour of the game.
Get into the Tower.
Find Sandra's diary.
Finish three Minigames in a row without skipping.
Confront Sandra's trauma.
Complete any Hidden Object Puzzle without using a hint.
Finish a Minigame in less than 1 minute.
Find your first Dreamer's Sheep.