An ancient stone gate glowing teal on a snowy plateau; four explorers stand at its foot.

Survey Directorate · Threshold Station

PROJECT
THRESHOLD

Survey Team Zero vanished nineteen days ago. This morning their beacon began transmitting again, in your voice.

A science-fiction roguelike deckbuilder. Lead a four-person team through an alien gate, build a new deck every run, and survive what waits beyond the threshold.

Play in your browser How it plays
  • Free · no install
  • Desktop & touch
  • English & Deutsch
  • One run ≈ 30 minutes

Expedition I — The Pale Verge

Something woke beneath the ice.

Eleven years ago, a gate was found beneath the Ross Ice Shelf. Its inscriptions are not words but star charts, and every chart opens a corridor to another world. They call the whole of it the Lattice.

Survey Team Zero walked into the Pale Verge and went silent on day three. Now their beacon is transmitting again. Commander Iona Vale leads Team One through to find out why.

“Whatever is using your voice out there, Commander, it does not get to keep it. Find Team Zero and bring them home.”

General Aco Threshold Station
General Aco on a steel gantry above the gate hall, arms crossed.
The gate under the ice shelf at night, auroras above.
Ross Ice Shelf
A holographic star chart of linked worlds.
The Lattice
Four explorers before the gate at dawn.
Team One
The gate fully open on a pale alien plateau.
The aperture

How to play

Read the hostile. Play your cards. Bring everyone home.

Every run is new: a generated map, new rewards, a different deck. If the team falls, you start again — with everything you have learned.

  1. 01

    Choose a corridor

    The Corridor Atlas branches across nine depths: hostiles, elite contacts, unknown signals, traders, forward bases and dormant artifacts. Every path ends at the Custodian.

  2. 02

    Read the intent

    Every hostile shows its next action above it: attack, guard, empower or suppress. Nothing is hidden — good turns come from reading it.

  3. 03

    Spend Command

    You draw five cards and have three Command per turn. Tap a card to select it, tap again to play it. Block absorbs the incoming attack and expires at the start of your turn.

  4. 04

    Combine disciplines

    Order matters: “After Science” strengthens a card if the previous one was Science. Three different disciplines in one turn trigger Team Synergy: draw 1 and gain 4 block.

  5. 05

    Build your deck

    After each victory, pick one of three cards — or none. Upgrade cards at a forward base, remove weak ones at a trader, and collect artifacts that bend the rules.

  6. 06

    Survive the Custodian

    Integrity carries from fight to fight. Pace yourself: the Aperture Custodian waits at the end — and below half integrity it grows more dangerous.

Block
Absorbs damage this round.
Exposed
Takes 50% more damage from your cards.
Burn
Damage at the start of the hostile turn, ignores block, drops by 1.
Weak
Each hostile hit deals 3 less damage.
Power
Adds damage to every hit for the combat.
Exhaust
Removed for this combat after it is played.

Cards

Every card is an order to your team.

Sen covers, Venn analyses, Marr builds, Vale coordinates. 24 cards and their upgrades — here is a selection.

1
Pulse Burst
ACTION · TACTICAL

Deal 6 damage. After Science: deal 4 more.

1
Spectral Scan
TACTIC · SCIENCE

Apply 1 Exposed. Draw 1.

1
Shield Relay
TECHNOLOGY · ENGINEERING

Gain 5 block. After Tactical: gain 3 more.

1
Synchronized Fire
ACTION · COMMAND

Deal 7. After Engineering: deal 7 more.

0
Shared Objective
PROTOCOL · COMMAND

Gain 1 Command. Exhaust.

2
Arc Lance
TECHNOLOGY · ENGINEERING

Deal 16 damage.

1
Ion Cascade
ACTION · SCIENCE

Apply 5 Burn.

2
Breach Charge
ACTION · TACTICAL

Apply 1 Exposed, then deal 14 damage.

1
Aegis Directive
PROTOCOL · COMMAND

Gain 8 block. Draw 1.

1
Needle Beam
ACTION · SCIENCE

Deal 6 damage. Apply 3 Burn.

2
Prismatic Strike
TECHNOLOGY · XENOTECHNOLOGY

Deal 12. Gain 10 block.

3
Full Salvo
ACTION · TACTICAL

Deal 30 damage.

Team One

Four specialists. One shared integrity.

Commander Iona Vale

Commander Iona Vale

Command

Leads Team One. Her orders buy Command, cards and block — and hold the team together.

Rook Sen

Rook Sen

Tactical

Point and cover. Direct damage, crossfire and hard cover when it counts.

Dr. Nara Venn

Dr. Nara Venn

Science

Reads the walls and the enemy. Exposes weak points, burns and jams hostiles.

Teo Marr

Teo Marr

Engineering

Keeps the aperture stable. Shields, power and heavy technology.

General Aco

General Aco

Threshold Station

Commands Threshold Station and every expedition that leaves it. Nobody gives up on his people.

The Glass Continuance

They show you what they will do. That does not make them less dangerous.

Hostile · tier 1

Glass Watcher

A single lens on mineral struts. It studies, then strikes.

Hostile · tier 1

Verge Skimmer

Glides on heat. Each pass sharpens its edges.

Hostile · tier 1

Filament Crawler

Low, quick and patient. It grows bolder each turn.

Hostile · tier 1

Signal Kite

A drifting jammer trailing static.

Hostile · tier 2

Shard Warden

A walking wall of fused plates.

Hostile · tier 2

Hollow Echo

An empty ring that repeats your signals back, broken.

Hostile · tier 2

Obsidian Sentry

Old perimeter defense, still keeping its orders.

Hostile · tier 2

Null Drifter

A loose swarm of shards orbiting nothing.

Elite

Prism Marshal

Commands the lesser glass. Builds up, then breaks you.

Elite

Static Choir

Three voices, one weapon.

Guardian

The Aperture Custodian

The corridor itself, awake and unwilling.

  • A painted world

    Painted scenes, characters and more than twenty card illustrations.

  • A voiced story

    A voiced briefing, radio chatter in the field and an original score. Subtitles in English or German.

  • Plays anywhere

    Mouse, keyboard or touch. Best in landscape on desktop or tablet.

  • Progress stays

    Every action autosaves in your browser. Pick up where you left off.

The aperture is stable. Mostly.

Free, no install, right in your browser. First load downloads about 28 MB.

Start the expedition

Questions

What do I need to play?

A current browser with WebGL 2: Chrome, Edge, Firefox or Safari 15 and later. Phones work; it is most comfortable in landscape on a larger screen.

Why is there no sound?

Browsers only allow audio after your first interaction. Click or tap the game once. Volumes are in Settings.

Where is my progress saved?

Locally in your browser on this device. There is no account and nothing is stored on a server. Clearing site data removes your save.

Can I change the language?

Yes: Settings → Language in the game. On first launch it follows your system language. Voices are English; subtitles are English or German.

How long is a run?

An expedition through the Pale Verge takes about 25 to 40 minutes. You can stop at any time and continue later.