Open playtest · October 12–25, 2026

Listen closely. Find a way through.

A sound-driven journey into an unfamiliar world. Start with the Steam playtest, find puzzle hints, and keep track of the Q1 2027 release window.

Read the playtest guide Puzzle help

Official Sublustrum screenshot of an old apartment with a large brass capsule, ceiling pipework and tall cabinets.

Field notes

Where are you in the journey?

Join the playtest

Dates, Steam access and what Chapter One includes.

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Stuck on a puzzle?

Read hints before revealing a solution.

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Check your PC

Compare the official minimum and recommended requirements.

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Waiting for release?

The current release window and confirmed platforms.

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Recent Updates

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Guides

Sublustrum Cooling Puzzle: Valve Hints and Source Check

Check the missing wheel, valve clues and disputed 6-0-2-3 sequence in Sublustrum's playtest cooling puzzle, with clear limits and community sources.

Guides

Sublustrum Fourth Valve: Where to Find the Missing Wheel

Find the missing fourth cooling valve in the Sublustrum playtest: the apartment's high cabinet and Echophone scan, with dated community sources.

Guides

Sublustrum Piano Puzzle: Playtest Slider Solution

Set the piano sliders to 2, 5, 7, 5, 4 with this community-reported Sublustrum playtest solution, including counting and chamber hints.

Guides

Sublustrum Playtest Guide: Access and Chapter One Help

Join the October 12–25 Sublustrum Steam playtest, check Chapter One puzzle help, and distinguish community hints from verified walkthrough steps.

Guides

Sublustrum Puzzle Guide: Piano, Valves and Sound Hints

Find Sublustrum playtest help by puzzle: piano sliders, the missing fourth cooling valve, and sound-driven mechanisms, with sources and spoiler labels.

Outcry & history

Outcry (2008) and Sublustrum: Original vs the New Game

Understand how Outcry, the 2008 Sublustrum original, differs from the upcoming 3D reimagining and why old walkthroughs cannot prove new puzzle answers.

Follow the signal

Choose a route through our guides and reference pages.

Playtest & puzzle help

Begin with Chapter One, then follow the puzzle clues.

Playtest guide

Access, scope and first steps

Puzzle guide

Clues, sounds and spoiler boundaries

Cooling puzzle

A focused look at the documented puzzle

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Release & PC information

Follow the official announcements, not outdated release listings.

Release window

Q1 2027; an exact date is not announced

PC requirements

Windows specifications from Steam

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Before Sublustrum

The 2008 game behind the new adventure.

Outcry (2008)

How the original relates to Sublustrum

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