Here is the full list of all 24 Summer of '58 achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Welcome to the pioneer camp.
You have fed the cats.
Russian wooden toy.
The first night in the camp came.
You were hit on the head.
Did you wake up after the impact.
Have you found a photo of the camp.
The second night in the camp came.
Have you read the director's story.
You've found the evidence.
You have collected all the photos in the camp, during correspondence.
You have reached an abandoned hospital.
The dead and the buried…
Have you packed all your things.
You picked up a pocket watch.