Identify the door and collect the tools
From the third-floor elevator, enter Ivan's apartment with the Apartment Key. If you want the opening knock achievement, handle it before unlocking the entrance; see the achievement checklist.
The study door inside has a red symbol and material sealing its edges. Collect the Old Book near the bedroom entrance for the recipe clue, then search these rooms:
| Object | Where to find it | What it does |
|---|---|---|
| Wrench | Bathroom, through the blue door beside the DEVORA poster | Breaks the bedroom-window boards |
| Developing Chemical | Kitchen, through the gray door beside the bathroom | Combines with the blood-filled Glass |
| Glass | Bedroom nightstand, opposite the boarded window | Collects blood from the bathroom mirror |
Make Auritsatio in the correct order
- Enter the bedroom through the door to the right of the TV. Open the curtains if needed, equip the Wrench and strike the boards on the window to the right.
- Continue until the lower board falls and sunlight is exposed. The important result is an opening for light, rather than merely inspecting the window.
- Return to the bathroom and stand in front of the broken mirror. Use the Glass from the inventory to obtain Glass with Blood.
- In the inventory, combine that blood-filled Glass with Developing Chemical. Confirm Glass with Chemical and Blood.
- Return to the opened bedroom window. Stand at the sunlight and use the mixture to obtain Auritsatio.
- Return to the red-sealed study door and use Auritsatio there. The seal clears and you can enter.
The object states make a useful progress check:
| What you currently hold | Interaction still needed | Expected result |
|---|---|---|
| Empty Glass | Use at the broken bathroom mirror | Glass with Blood |
| Glass with Blood | Combine with Developing Chemical | Glass with Chemical and Blood |
| Glass with Chemical and Blood | Use at the opened bedroom window | Auritsatio |
| Auritsatio | Use at the red-sealed study door | Study access |
If the seal does not open
| Problem | Check |
|---|---|
| The Apartment Key does nothing at the study | Select Auritsatio; the two doors have different requirements |
| The window gives no reaction | Break the board with an equipped Wrench before using the mixture |
| You still have an empty Glass | Use it while standing at the broken mirror, not at a sink |
| The mixture has not changed into Auritsatio | Complete the chemical combination and sunlight step before returning to the seal |
| You are trying to use moonlight | This opening recipe uses sunlight; the later bottle and knife tasks have their own moonlight guide |
There is no numeric password to enter for this seal. Use the finished item at the door; carrying it without selecting use does not perform the interaction.
Confirm success and continue
Study access is the completion signal. Finish the encounter that follows and return to the elevator. The main route then moves to the second-floor apartment, the batteries and TV-symbol puzzle.
Resume the apartment checkpoint in the walkthrough for that transition. If you already hold a late-game knife, you are past this opening recipe: follow the Desiderium photographs and knife route, which makes a separate batch of Auritsatio.
Sources
- Official Puzzle & Boss Guide, section 1: item locations, mirror blood, window boards and recipe; publisher's pinned link.
- Into Indie Games, Part 1: opening study and apartment progression.
Source-checked October 23, 2026, using the official guide retained during this site's first research round and the linked release walkthrough. This site does not claim an independently captured playthrough.