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