Here is the full list of all 20 35MM achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Assemble the children's puzzle
Help to grandfather in town
Find the bodyes of hanged people over the railway
Listen the sound anomaly at the first location
Light a candles in an abandoned church
Kill grandmother in the old village
Rate the abstract picture on location "Bor"
Find "easter egg" from the first game of author
Find the secret documents in the safe
Listen to the radio signal in tunnels
Find anomalous zone in the tunnels
Give your partner a first aid kit
Kill all dogs without reloading weapons
Call to Hell
Open the safe in the city
Find a room with mannequins in city
Die
Reach the finals alone
Reach the finals with a partner
Listen the airwaves in the hospital