THAWLINE

Learn what the mountain is made of by risking your hands on it, then abandon everything you built before the frost finishes learning your name.

Survival Crafting PC (Windows) KBM + Controller Early Access · $27.99 Concept · 2026-08-03

One season. Eight valleys. An ending.

The World

The Kestrel Range used to have four seasons. A geothermal drilling operation went wrong nine years ago and seeded the rock with rimeglass — a crystal that grows toward cold and standing structures, and hasn't stopped since. The government pulled out. You didn't get a map, a recipe book, or a radio contact. What you know, you'll learn by burning your hand on it.

Core Loop

30-Second Play

Unlabeled ore chips, a fibrous strip that smells like ozone, forty minutes of daylight. Nothing tells you what they make together. You note the weight, the smell, and commit. The bench sparks — a heat conductor, not the rope you guessed. You write down what you learned, in your own words, because the game never will.

Core Loop

30-Minute Run

Camp in a hollow — lean-to, fire pit, drying rack. The frost line has been creeping toward your fire all afternoon; it's eight meters out now. One more gamble, a fire starter that just barely works, then you tear down and haul north before the hollow goes under. The lean-to is already sugared with crystal behind you. You won't see it again.

Where it gets boring in hour three: once a player learns the common ores in the first valley, experimentation stops being a puzzle and starts being a lookup. Each of the eight valleys introduces materials that read as familiar but behave differently at altitude — the same ore that's a fine conductor at sea level is an explosive hazard above the frost line. A trusted journal becomes a source of confident wrong guesses. That's the hook the genre's recipe trees can't offer: prior mastery that can hurt you, on purpose.

Key systems

Interlocking Systems

🧪

Blind-Bench Crafting

No recipe list. Materials have hidden properties revealed only by sensory tells — weight, smell, the way they catch firelight. Every combination is a real gamble with three outcomes: a working item, a wasted attempt, or a bad reaction.

❄️

The Frost Line

Rimeglass spreads from fixed source points. Structures left standing too long crystallize and are lost for good — tools and stored materials included. The spread rate is visible and predictable, so losing a camp is a decision, not bad luck.

🎒

The Rig

Sled and backpack slots define what survives a relocation. Sleds carry more but can't cross narrow ledges. Every teardown is a real packing choice — you can't carry the whole camp.

🌬️

Weather as a Second Clock

Wind affects scent-tracking and fire viability. Whiteout storms cut visibility and tighten the timing window on workbench attempts. No combat AI — the mountain just makes everything else harder at once.

🕯️

Ghost Camps

Crystallized remains of a previous expedition, with a legible but incomplete scrap of someone else's journal. Static, single-player content that seeds partial knowledge and dread without breaking the isolation.

🗻

The Pass Clock

Every mountain pass seals permanently at a fixed point in the season, visible from the start. Reach the Solstice Relay before the last pass closes. Every closure is telegraphed at least two in-game days ahead.

Key features — copyable for your pitch deck

Key Features

Crafting Has No Menu
Every combination is a real experiment with three possible outcomes, logged by the player's own hand into an in-fiction journal — not unlocked from a tech tree. Prior mastery can actively mislead you at altitude.
Every Camp Has a Shelf Life
The frost line crystallizes anything left standing too long. The reward for skill is packing lean and moving on — not sprawling into a permanent base, the default fantasy in most of the genre.
The Season Ends
A fixed pass-closure clock, visible from minute one, replaces the endless-grind structure that has burned out veteran survival players. Roughly 10–14 hours, then it's over — win or don't.
Single-Player, On Purpose
No live co-op. Ghost camps — static remains of past expeditions — seed knowledge and dread without breaking the isolation the setting depends on.
Weather Without Combat
Wind, cold, and whiteouts pressure every other system at once — scent-tracking, fire viability, crafting precision. The mountain is the only antagonist, and it's always on the clock.
An Honest New Game+
"A Harder Winter" reshuffles which sensory tell maps to which material property and tightens every timer, so a veteran's journal from run one becomes actively misleading.

Risk register

Honest Risks & Mitigations

Risk	Type	Mitigation
Blind crafting reads as guesswork	Design	Week 1 tests tell legibility alone, before any other system
Relocation feels punishing, not purposeful	Design	Generous early timers, visible spread rate, timer-extension assist option
Single-player pricing limits revenue	Market	Priced against The Long Dark / Firewatch-tier premium single-player, not live-service scale
Fixed ending caps replay hours	Market	Seeded valley variation, New Game+, expedition-time leaderboards
Three interacting systems is real scope	Scope	Prototype order tests the novel system (crafting) first; frost and weather use established patterns

6-week prototype path

Prototype Plan

Week 1Blind-bench crafting in isolation — 15 materials, sensory tells, three-outcome resolution, journal prompt. No world yet. External playtest on tell legibility.

Week 2Single graybox valley, one frost source point, visible spread rate, structures that crystallize and are lost.

Week 3Rig system — sled and backpack slots, terrain penalties, teardown/rebuild flow. Two valleys connected by one pass.

Week 4Weather layer — wind, temperature, whiteout storms — layered onto the existing frost and rig systems.

Week 5Ghost camps, pass-clock overview map with telegraphed closures, season-pacing pass across three valleys.

Week 6Vertical slice: three valleys, one pass closure, one full relocation cycle, placeholder Relay checkpoint. External playtest and tuning pass. Stakeholder presentation build.