The Tartarus Key Guide – Puzzle Hint, Solution, Achievement

The Tartarus Key is full of strange rooms, hidden clues, puzzle mechanisms, and decisions that can determine whether your companions survive. While most of the puzzles are manageable once you understand what the game is asking you to look for, a few of them can definitely leave you stuck for longer than expected.

In this post, I will walk you through the puzzles in The Tartarus Key, including hints for players who want to figure things out themselves and direct solutions for anyone who simply wants to continue. We will also go through the choices needed to unlock the game’s achievements.

The guide follows the approximate order in which you encounter the puzzles during the game. You might complete a few things in a slightly different order depending on how you explore, but everything listed here is connected to progressing toward the different endings.

The Tartarus Key Guide – Puzzle Hints, Solutions, Achievements

The estimated difficulty for getting everything done is around 2/10, while reaching 100% can take roughly 4–6 hours. You will also need two playthroughs to see the three different endings and unlock everything.

Escape the First Room

The first puzzle requires you to enter four separate numbers.

Hints

  • You need to find four different numbers.
  • Look around for postcards scattered through the area.
  • Pay attention to the numbers that have been circled.
  • You should also find a list containing travel dates.
  • Use the travel dates and the hidden number inside each postcard message to arrange them according to the order in which each country was visited.

Solution

7341

House Guest Achievement

You unlock House Guest simply by escaping the office.

Paintings of Bottles

For this puzzle, you need to place the potions in the correct order.

Hints

  • Make sure you have collected all of the potions.
  • The directions of the tears in the bottle paintings are important.
  • The white potion belongs in the middle because its painting has a tear on both sides.
  • The tears point toward the white bottle.

Solution

From left to right:

Black, Yellow, White, Red, Green

Chatty Achievement

You unlock Chatty by using the radio repeatedly.

My advice is simple: interact with the radio whenever the game gives you an opportunity. It should be fairly difficult to miss if you keep using it throughout your playthrough.

Saving Torres

To save Torres, you need to pay attention to the letters found around the room.

Hints

  • The letters on the wall can be completed using letters found somewhere else.
  • This puzzle is actually quite straightforward once you locate both parts.

Solution

Combine the letters on the wall with the letters on the mirror. Check the painting afterward and use the axe to break the wall behind it.

Doing My Best?! Achievement

You unlock Doing My Best?! by hurting Torres.

Use the axe on Torres’ door to unlock it.

Doing My Best! Achievement

You unlock Doing My Best! by successfully helping Torres.

Use the axe on the wall behind the painting instead.

First Floor Library

The library contains multiple puzzles that you need to solve.

Weapon’s Case

Hints

  • Read every book in the room and remember the dates mentioned.
  • Pay attention to which weapon each murderer uses.
  • If one person does not have a date, check whether they were mentioned somewhere else.
  • The Dream Dealer is mentioned in another book.
  • Use the killers’ weapons and their active years to determine the order of the buttons.

Solution

4-2-1-3-5

Bookshelf

Hints

  • The arrows behind the books tell you which side the books should be placed on.
  • Turning the items around in your inventory reveals numbers.
  • The painting tells you which items matter.

Solution

  • Top shelf: 1 right
  • Middle shelf: 5 left
  • Bottom shelf: 3 right

Religious Mural

For this puzzle, you need to light all of the buttons at the same time.

Hints

  • Every button needs to be lit simultaneously.
  • The statues and the mural are connected.
  • The physical locations of the creatures on the mural correspond to the locations of the symbols on the pedestal.

Solution

The dots are:

1-2-3-4-5

The creature positions are:

  • Angel: 3rd
  • Minotaur: 5th
  • Lamia: 1st
  • Knight: 4th
  • Demon: 2nd

Saving Charles

You need to find five symbols and speak with Charles about each of them.

Hints

  • Locate all five symbols.
  • Speak to Charles about every symbol you find.
  • The directions of Charles and the monsters are important, with North serving as the reference point.

Solution

  • North – Andromalius
  • East – Bifrons
  • South – Raum
  • West – Malthus

Doing What He Loved Achievement

You unlock Doing What He Loved by solving Charles’ puzzle incorrectly.

History Lesson Achievement

You unlock History Lesson by solving Charles’ puzzle correctly.

Second Floor Master Bedroom

There are several puzzles to complete inside the master bedroom.

Note

Hints

  • You need a sticky note to begin this puzzle, and you must move an object to find it.
  • Place the projector slide in and determine which room it corresponds to.
  • Increasing your PC brightness can help, although you still need to locate where each number belongs.
  • Hidden symbols show four squares and an arrow, matching the positions indicated by the numbers.
  • Use the sticky note code and shift the numbers, beginning with the pattern at wall 1, then wall 2, and so on.

Solution

1925

Dressing Table

Hints

  • With the next projector slide, you need to highlight three buttons.
  • Look carefully at the button arrangement and which numbers represent each button.

Solution

  • Row 1 – Symbol 3: Triangle
  • Row 2 – Symbol 3: X
  • Row 3 – Symbol 2: Circle

Crystal

For this one, you need to use the projector and create the correct shadows.

Solution

Build the door by positioning things so the projector casts the required shadows.

Astronomy Room

This room uses several different notes and pieces of information.

Hints

  • You have three notes, a blackboard, an empty binder, and a journal to work with.
  • The pen colors on the notes correspond to the journal names.
  • You only need four animals and four compass directions.
  • The empty binder helps explain where they should be placed.
  • Jeffrey’s dates are written backwards.
  • When Jason tells Jonathan to meet in the middle, take that literally and look for the animal they share.

Solution

  • North – Unicorn is locked: 25/07
  • East – Wolf is locked: 08/03
  • South – Whale is locked: 11/08
  • West – Raven is locked: 06/05

William’s Room

William’s room contains an electric grid puzzle, a safe, and the puzzle needed to save him.

Electric Grid

Hints

  • Examine the painting and speak with William.
  • Pull back the rug and inspect the box underneath.
  • Think of the puzzle as a game where you connect electrical wires.
  • The orange dots around the puzzle turn blue when the nodes are connected properly.
  • While facing the painting, the middle-right piece provides power to the rest of the grid. Connect everything to it.

Solution

Connect the grid so every required node receives power from the important middle-right section.

The Safe

Hints

  • Look at the grid again.
  • After William moves, examine the book he leaves behind.
  • Numbering the grid from 1–9 is not important.
  • There is a clue underneath the symbol list on the book cover.
  • Partial symbols inside the squares can be combined to create one of four complete symbols.
  • Compare the partial symbols used to create a symbol with the spaces on the grid and draw the pattern out.

Solution

5423

Saving William

William’s book tells you that he drank a Gumshoe, which gives you the information needed for his drink.

Hints

  • The drink has very specific instructions.
  • Water can be found somewhere in the room.
  • Two ingredients need to be swapped, while the cordial alternative is listed on another page.
  • The drink needs to be served piping hot, which does not mean simply adding coffee at the end.
  • Look at what William is now standing near.

Solution

Use:

  • 1x Whiskey
  • 1x Liqueur
  • 2x Coffee

Once prepared, warm the drink by the fire before giving it to William.

A Stiff Drink Achievement

You unlock A Stiff Drink by making William the wrong drink.

The Music Was Nice Achievement

You unlock The Music Was Nice by preparing William’s drink correctly.

Basement and Saving Kai

The basement contains several puzzles, including the sequence required to save Kai.

Saving Kai

Hints

  • You need a cloth and a lighter.
  • Kai’s test tube has wires that can be manipulated.
  • Cloth can be used for cleaning.

Solution

Use the cloth to clean the blood on the floor and obtain a DNA sample.

Once the countdown begins and the locker behind you opens, grab the screwdriver and ID. Examine the uniforms to find the lighter.

Use the ID to stop the lockdown. Then use the screwdriver on the panel at the bottom of Kai’s tube. Finally, use the lighter to turn off the life-support system.

Storage Room Code

Hints

Everything required for this code is inside the storage room itself.

Solution

6322

Meat Freezer

For this puzzle, you need to move the piece of meat with the ribbon to the meat cutter.

The original puzzle solution is based on following the required movement path through the freezer.

Kitchen

The kitchen puzzle requires six pages and the chalkboard.

Hints

  • Collect all six pages and examine the chalkboard.
  • Find the wheel and determine where it belongs.
  • Once placed, something else will turn on.
  • Check which recipes shown on the board you are actually able to prepare.
  • Use the chalkboard to identify the two recipes and compare the ingredient placement in their pictures with the stove burners.

Solution

The two recipes available are:

Friday Chicken Madras + Beef Stew

For the stoves:

  • On the left stovetop, light the two burners on the right side.
  • On the right stovetop, light every burner except the top-right one.

Prison Cell

This puzzle works differently from many of the others because the information is used across several stages.

Hints

  • You need three different pieces of information.
  • Focus carefully on the paper the computer provides after each test.

For the individual tests:

  • Test 1: Follow the arrows.
  • Test 2: Only one of the letter strings is correct.
  • Test 3: Read the information carefully because it can easily trick you.

Solution

Test 1:

Up, Right, Down, Down, Right, Right

Test 2:

BCDACBD

Test 3:

Heart, Club, Spade, Heart, Club, Spade

Electric Solitaire Achievement

You unlock Electric Solitaire by solving Kai’s puzzle incorrectly.

Co-op Achievement

You unlock Co-op by solving Kai’s puzzle correctly.

Cleaning Closet Doors

The cleaning closet contains several locked doors, each using a different solution.

Hints

  • After connecting the wires, everything you need is inside the room.
  • Turn on the device connected to the wires and check the number pad.
  • For the next door, use reading order.
  • For the third door, look at what the nine squares resemble in the room.
  • For the fourth door, think about where you have seen the symbol before.

Solution

First, use the red tape on the floor to repair the wires and turn on the blacklight.

The door solutions are:

  • 2940
  • Spade, Heart, Diamond, Spade, Diamond
  • BPPYYPPBY
  • Form an upward-pointing triangle with an eye near the bottom

Clinic and Saving Ruth

The clinic contains multiple puzzles before you can successfully save Ruth.

Clinic Button

Save your game before trying this one if possible.

Solution

  • Bottom right dial
  • Bottom left dial
  • Bottom right dial
  • Bottom right dial

Clinic Skeleton

First, place the brain inside the specimen jar so the skeleton moves.

Hints

The poster shows the pose you need to recreate.

Solution

Make the skeleton match the poster exactly, including the crooked arm.

Saving Ruth

Hints

  • You need three Greek-symbol chemicals and a syringe.
  • There is also a centrifuge and a beaker.
  • Think about what should go inside the syringe and scan it.
  • The books provide important information.
  • You are missing something that is not immediately visible in the room.
  • Look carefully at the walls.
  • Once you have the required items, determine which element is missing from the antidote.
  • You do not need everything inside the bottle, so think about how you can separate its contents.
  • The poster is also important.

Solution

Draw blood using the syringe and place it inside the centrifuge.

The books reveal that you need Tau. Move the bookshelf to uncover a hole in the wall where Tau can be found.

Put the antidote into the centrifuge to separate it and retrieve the Tau.

Finally, combine:

Tau + Alpha + Drawn Blood

Horrible Science Achievement

You unlock Horrible Science by solving Ruth’s puzzle incorrectly.

Elementary Achievement

You unlock Elementary by solving Ruth’s puzzle correctly.

Sole Survivor Achievement

To unlock Sole Survivor, every possible companion needs to die.

After completing the final puzzle in the mansion, allow the final stranger to die as well.

Elevator and Offices

Once you finish the mansion puzzles, you can use the elevator to reach a new office area containing a few final puzzles.

Box

Hints

  • You need the swords and must locate four animals around the room.
  • The whale is probably the trickiest one.
  • Look carefully at the shape of the origami.

Solution

  • Whale – Bottom
  • Bird – Bottom Left
  • Unicorn – Top Right
  • Wolf – Bottom

Turning on the Controls

Hints

  • The whiteboard and colorful computers are important.
  • You specifically need to use the white spheres.
  • Once you know the colors needed, figure out their order using color mixing.
  • Red and yellow make orange.
  • Blue and yellow make green.
  • Red and blue make purple.
  • The whiteboard shows both the directions and colors.

Solution

From left to right, the white lights should be:

Pink – Orange – Green

Use the color wheel to create the required colors.

Group Effort Achievement

You unlock Group Effort by rescuing all companions and escaping together.

Secret Ending Area

The secret ending requires you to access an additional hidden area.

Secret Location

Hint

Use the projector.

Solution

Return to the barrel room near the elevator. In the back room, interact with the third barrel from the left.

Tomb

Hints

  • You need three statues.
  • The third statue is hidden inside the room.
  • Even if the gargoyle is difficult to read, you can still work out the symbols.
  • The correct order is shown elsewhere in the room.

Solution

The third statue is located inside an open coffin.

Bottom of the Well and Lasers

Hints

  • You can swap the symbols on the ground to redirect the laser.
  • The symbols on the tree can also be turned.
  • Depending on your solution, one of the trees is not required to complete the puzzle.

The goal is to arrange the symbols so the laser follows the correct path.

Red Space

This area requires you to recreate events from different scenes.

Solution

Bathroom

Examine the painting and throw the axe.

Clinic

Examine the wall and pick up the bone saw.

Lab

Leave the lab and go upstairs to break the door.

Cartographer Achievement

Cartographer can only be unlocked while going for the secret ending because the additional areas count toward completing your map.

After reaching the laser puzzle, open your map and the achievement should unlock.

Until the Bitter End Achievement

You unlock Until the Bitter End by completing the secret ending while keeping most or all of your companions alive.

The achievement is connected to the secret ending and the goal of saving the world, so make sure you are following the correct ending path and avoiding unnecessary companion deaths.