Here is the full list of all 42 DreadOut achievements.
Playing DreadOut on Thursday night
Playing DreadOut without any clues
Playing DreadOut with convenience
Finished the game without entering Limbo in Act 1
Reached an alternate ending
It's a cute way to die
Dial the correct number
Finished DreadOut
Found the secret of the mansion
:P~
Took a picture of Gundul Pringis
Solved the mistery of the crying widow
Took a picture of Palasik
Deal with Suzzie
Listen to her story
Resistance is futile against the hand of fate
Banish many Pocongs in single shot
Solved graveyard puzzle
Acquired the Camera
Collected all ghost pictures
Collected all special items
Collected all articles
Took a picture of Genderuwo
Took a picture of Pocong on a motorcycle
Took a picture of UFOs
Took a picture of Betsy
Thank You
Endured all the scary moments on DreadOut so far
Solved all puzzles
Left the school
Travelled for a long distance
Defeated the school principal's ghost
Stay scanning for ghosts
Added any picture to the gallery
Entered Limbo
Solved a puzzle
Took a picture of Sundel Bolong at the school cafeteria
Took a picture of the cat
Took a picture of a ghost
Trapped alone
Found an article
Took a picture of Shakira Irawati