Here is the full list of all 36 The Invisible Hours achievements.
Watch Mundy's death
Watch Gustav's fall
Discover who killed Tesla
Travel back in time with Flora
Explore the entire Island
Watch Vanderberg's murder
Find the secret workshop in the basement
Find the Ulysses poem
Find the library receipt
Watch Bernhardt and Mundy recite Shakespeare
Find Deadlight logo
Find the first Tesla Diary
Find the fox
Find the chemistry notes
Be walked through by a character
Activate Following mode
Watch all the scenes in chapter 1
Watch all the scenes in chapter 2
Watch all the scenes in chapter 3
Watch all the scenes in chapter 4
Go to the hotel room
Find Lafcadio Boone's mask
Use the Spirit Radio
Watch Gustav for the entire game
Collect all the clues
Watch Bernhardt putting on makeup
Watch Edison play chess
Find all of Tesla's diaries
Find all the newspapers clips
Find old photos of all the characters
Find all the letters from the guests
Find the hats
Look through the telescope
Listen to the lullaby
Find Edison's food bowl
Try to bang the gong