This guide was finished on 26. Feb 2017

If you can help adding information that is lacking or correct any mistakes I made in the guide, please write it in the comments or contact me directly. I want this guide to be as thorough, comprehensible and accessible as possible. I will also happily include complete translations if anyone can provide them.

Furthermore I want to give credit to all the people that helped completing the guide, especially with the elusive secrets: ShivaRoodels, Kaseteufel, ZenekZombie, gwabgwab, Shymain, Josiah1221, HuadanNox, Seagull Solo, Arriving Raptor

The Good Doctor
Description: Watch a patient's clinical progress.
Requirements: You discover a strapped patient behind a fake mirror early on. You need to inspect him at 4 different points in the story:

1. When you see him the first time.
   
2. After you got the mask from the "Paul Street" location.
   
3. After you show the mask to Miss Konhe (and get attacked).
   
4. After you obtained the fake eyeball from the inmate quarters.

The achievement will unlock once you leave the room with the fake mirror after checking in on the patient the 4th time.

Safe Cracker
Description: Listen carefully.
Requirements: Open the safe in Paul Street without revealing the code on the pieces of paper you find. If you listen very closely the sound of turning the dial is slightly different when you hit the correct number. So you can deduce the correct combination without knowing it. The combination is 6-1-4-5.

They are Coming
Description: Complete the first episode.
Requirements: self-explanatory

Master of Hypnotism
Description: Explore the depths of the subconscious mind.
Requirements: You need to visit every location possible in the hypnosis session. These are the commands for the shortest route:

• Go elsewhere - Wait here until an additional dialogue option appears then take it.
  
• Walk towards the fog
  
• Go back
  
• Go West
  
• Go West
  
• Go back
  
• Go North
  
• Go North
  
• Go back
  
• Go East
  
• Go East
  
• Go South
  
• Go back
  
• Go North - After this you will only have one option, follow it to the end.

Lost in the Sea
Description: Learn of who disappeared in the cliffs.
Requirements: After you put down the flowers at the graveyard and the church bell rings, go back to the town square and directly down to the beach. When you enter that screen wait a moment and you will see a necklace wash ashore. Take it quickly since it can get swept away again. Give this to the person in the window that gave you the flowers earlier.
Later, near the end of the episode, when you navigate the cave, you will come across a skeleton. Inspect it and the achievement should activate.

Fear Itself
Description: Complete the Second Episode.
Requirements: self-explanatory

You Seem So Certain
Description: Confess your beliefs.
Requirements: When talking to Lord Donnán answer his questions as you please. This seems to be an automatic achievement.

The Wicker Man
Description: Find all burning statues.
Requirements: There are 4 statues in total. They appear at the following locations and will start burning after a certain point of progression:
Solitary House - after exploring the basement and reading the diary
Old Abbey - after opening the hidden passage
Donnán Manor (after repairing the bicycle) - take the iron disc after meeting the man with the mask
Lighthouse - after repairing the lighthouse
Important: Inspect each burning statue!

Description: Complete the Third Episode.
Requirements: self-explanatory

Performer
Description: Show your ability at the keys.
Requirements: After you found the music sheet and the missing piano key, play the melody correctly on the first try. Since the sheet is mirrored, the correct order is reversed.
The picture below shows in what order you have to push the keys.
Devitt's Fate
Description: Save Devitt's life,
Requirements: When Alexandre confronts you with the choice of going through the curtain, do it.

Wakefield's Fate
Description: Save Wakefield's life.
Requirements: When Alexandre confronts you with the choice of going through the curtain, leave the stage.

The Whole Story
Description: Read all letters, notes and diaries in the game.
Requirements: Almost all of the things you need for this achievement are required for story progression and can not be missed.
This list shows only those items that might be overlooked by episode.

1. East Hill - In the room with the mirror there is a therapy log pinned to the wall.
   
2. Wright Manor - In the library on the bookshelf next to the fireplace you can find the book "The Travels of Marco Polo" after you get your first hint from Professor Wright.
   Read the notes that Wakefield keeps for each part of the riddle in the mansion.
   Wright Manor (second time) - Read the book found on the floor of Wright's bedroom.
   Cliff - After opening the passage to the cave there is a note on the floor right at the entrance.
   
3. All items in this episode are mandatory and can not be missed.

This achievement should unlock by the end of episode 3.

The New Bearer
Description: Complete The Mask with no Eyes
Requirements: Play through the Minisode "The Mask with no Eyes" found in the Extras menu.

Neophyte
Description: Discover your first secret.
Requirements: This guide features a complete list of all secrets in the game further down. Choose any of them to get this achievement.

Playwright
Description: Discover all secrets.
Requirements: There are 11 secrets to find for this achievement. They are listed here in roughly the order that you encounter them in game.

Episode 1:
Secret 01
Paul Street - Alexandre's hideout
The safe in the bricked up house can be opened with 2 combinations. Regularly you would find it on the pieces of paper nearby and use 6-1-4-5. However if you reverse that combination (5-4-1-6) the safe will open as well and once you enter the hideout a cutscene starts playing.

Secret 02
East Hill - Inmate quarters - first room
Walk around the room and step on multiple insects indicated by squishing sounds. If you stepped on enough of them the person will start talking to you.

Episode 2:
Secret 03
During the episode you navigate Professor Wright through his subconsciousness. Right at the beginning you get the option to "go elsewhere". Initially there is nothing to be found there but after waiting a bit he will say he sees something and you get a new option. At that point you can "Walk towards the fog" which discovers this secret.

Secret 04
This secret is the same as the Lost in the Sea achievment in Episode 2. Just follow the instructions given in the earlier part of this guide.

Secret 05
On the cliff there is a crack in the wall outside the house. Stand close to it and after a moment you will hear a roar/moan/cry. Wakefield will respond to the sound.

Episode 3:
Secret 06
At the start of the episode you have to tell Lord Donnán that you are religious. Later in the episode, after you have used the iron disc to open the secret passage, go back to the Hills and north to the marsh. There should now be a crucified wicker in the water. Inspect it and you're done.

Secret 07
Once you enter the graveyard inspect the first top tombstone. The tombstone will only be active after your first playthrough of this episode. So you will need to repeat it.

Secret 08
When you discover the hole on top of the hill, inpect it several times. After around 4 times Wakefield will not have a monologue but instead you will hear a sound coming from the hole.

Episode 4:
Secret 09
When you enter the house at the early stage of this episode there is a picture frame to the left of the entrance. Inspect it and stay in the close up of that painting. After a while you will hear what sounds like a baby crying. This sound will change to something monstrous. Wait until the complete transition is done (takes about a minute).

Secret 10
Early on in the episode you enter a house. To the left you can enter the basement. Once you get in it takes about 2 minutes and a dripping sound will start. It takes about 3 minutes to finish and the drops stop. This is when the secret is registered as discovered. Careful! If you leave the room the sound will continue but the secret not registered, so stay until it is done. In that case you can enter the basement again and the dripping will once again start from the beginning. If it still doesn't work I recommend you restart your game.

Secret 11
Once you put the missing key back into the piano and placed the music sheet on it you can start playing it. If you play one of two known secret melodies and leave the room with the piano the secret will count as discovered.
Working melodies are (Notes used in english language, notation differs in other languages):
Fa#, Fa#, La, Sol#, Fa#, Mi, Fa# - Monkey Island Theme
Fa#, Sol, La, Re, Mi, Fa#, Sol - Indiana Jones Theme