Set Hellion as the primary gameplay design baseline

README.md

@@ -2,6 +2,8 @@
 
 Frontier Systems is a cooperative, persistent engineering simulation set across Moon and Mars colonies, spacecraft, and orbital infrastructure. First-party code and created assets are licensed under MIT; see `THIRD_PARTY_NOTICES.md` before adding external content.
 
+The long-term design target is an independently implemented gameplay and mechanics remake as faithful to [HELLION](https://steamcommunity.com/app/588210) as practical, followed by additions from other games. This is a target, not a claim of current parity or official affiliation. See the [design baseline and priorities](docs/design/hellion-baseline.md).
+
 Visit the [Frontier Systems website](https://frontier-systems.discordphp.org/) for the game overview, [fundraisers](https://frontier-systems.discordphp.org/support.html) and [release availability](https://frontier-systems.discordphp.org/buy.html). The game is in development; support is not a finished-game preorder.
 
 ## Current foundation

docs/design/civilization-to-space-progression.md

@@ -4,7 +4,7 @@
 
 The project owner specified a later game mode/update where players start on a planet and develop a civilization through successive technological capabilities until reaching the space age. Civ13 is the primary reference for this milestone. The owner reports being one of its lead developers and explicitly authorizes consultation of any Civ13 code and assets as references.
 
-The first playable continues to prioritize environmental extraction, container storage, refining and recycling. Civilization progression builds on that resource loop after it is playable. No civilization runtime or technology unlocks are implemented by this document.
+The [HELLION gameplay baseline](hellion-baseline.md) is the primary project-wide direction. The already established extraction, container, refining and recycling prototype is an incremental foundation toward that direction; its completion does not establish HELLION parity. Civ13 remains the primary reference for this later planet-start extension, which layers onto the space-survival baseline. No civilization runtime or technology unlocks are implemented by this document.
 
 ## Gameplay direction
 

docs/design/hellion-baseline.md

@@ -0,0 +1,23 @@
+# HELLION gameplay and mechanics baseline
+
+## Direction
+
+Frontier Systems aims to be as close as practical to a faithful gameplay and mechanics remake of [HELLION](https://steamcommunity.com/app/588210), then add mechanics from other games on top. HELLION is the primary project-wide baseline, not one of several equally weighted inspirations. This direction concerns Frontier Systems, not Civ13.
+
+The original game's [Steam community description](https://steamcommunity.com/app/588210) presents stranded survivors exploring derelict ships and stations and acquiring air, fuel and equipment. The [Steam store page](https://store.steampowered.com/app/588210/HELLION/) attributes HELLION to Zero Gravity and describes a multiplayer space-survival simulation. These public descriptions were consulted on 2026-10-29; they are mutable and do not establish a detailed mechanics inventory or version-specific behavior.
+
+This is a design target, not a claim that Frontier has implemented or verified HELLION feature parity. The current [first playable](../development/first-playable-milestone.md) is a bounded cooperative extraction/refining/recycling prototype. Existing design contracts include project-specific proposals that must not be attributed to HELLION without evidence.
+
+## Order of work
+
+1. **Establish the baseline:** research observable gameplay and mechanics from rights-respecting public material, recording source, game version, access date, coverage and uncertainty in the [research manifest](../research/reference-manifest.csv). Build a reviewable capability map and identify independent acceptance scenarios; do not guess a complete feature list from a store summary.
+2. **Build toward faithful gameplay:** prioritize bounded, testable slices of the HELLION baseline and their required simulation, multiplayer, persistence and presentation foundations. Reuse current infrastructure where it serves the target. The existing prototype remains a useful foundation, not a parity milestone.
+3. **Layer other mechanics:** after the relevant baseline behavior is understood and established, evaluate additions from other games against it. Civ13 remains the primary reference for the later planet-start civilization extension; Moonbase Alpha and other references contribute secondary ideas. Preserve independently authored rules and explicitly document changes to the baseline experience.
+
+This order sets design priority, not a claim that every prerequisite must be completed before a small playable slice can be tested. For each slice record the target behavior, source and game version, current Frontier status, acceptance scenario and any intentional difference. Where an existing Frontier rule conflicts with a verified baseline behavior, surface the tradeoff for an explicit project decision; do not silently label the difference as parity. Do not infer that an unreviewed HELLION feature exists, or promise exact balance, content, networking or release timing.
+
+## Implementation and rights
+
+Frontier Systems is an independent project and is not presented as officially affiliated with or endorsed by HELLION or Zero Gravity. A gameplay reference does not grant rights to proprietary source code, assets, audio, maps, names, branding, UI layouts or text. Implement independently and use original or rights-cleared materials under the repository's MIT and creative-asset policies. Do not import or adapt HELLION files without independently verified file-level rights and the required approval.
+
+No runtime, content, asset or networking change is made by this design decision. Parity requires feature-specific evidence against identified HELLION versions and separately verified Frontier behavior; no current percentage or full-parity assertion is justified.

docs/design/moonbase-alpha-inspiration.md

@@ -1,6 +1,6 @@
 # Moonbase Alpha gameplay inspiration
 
-Owner-requested reference, reviewed 2026-10-11 UTC. This means NASA's 2010 game, not the television setting. These are independently authored Frontier Systems proposals, not implemented features or release promises.
+Owner-requested reference, reviewed 2026-10-11 UTC. This means NASA's 2010 game, not the television setting. [HELLION is the primary gameplay and mechanics baseline](hellion-baseline.md); Moonbase Alpha contributes possible later additions on top of that baseline. The priority labels below order this extension's own candidates, not the project-wide baseline. These are independently authored Frontier Systems proposals, not implemented features or release promises.
 
 ## Reviewed evidence
 

docs/design/procedural-planets-and-memory-budgets.md

@@ -2,7 +2,7 @@
 
 ## Direction and status
 
-A future expansion should support complete explorable procedural planets, with the scale and variety requested by the owner through the No Man's Sky reference. Use independently authored generators, definitions and assets. Mars and the Moon remain the initial destinations; later generated planets, moons, asteroids and orbital salvage regions share the same generation/streaming contracts.
+After the relevant [HELLION gameplay baseline](hellion-baseline.md) is established, a future extension should support complete explorable procedural planets, with the scale and variety requested by the owner through the No Man's Sky reference. Use independently authored generators, definitions and assets. Mars and the Moon remain the initial destinations; later generated planets, moons, asteroids and orbital salvage regions share the same generation/streaming contracts.
 
 **Planned, not implemented:** current procedural habitat meshes and homogeneous terrain material records do not generate planets, stream terrain or support voxel excavation. A complete planet must be representable without allocating its complete surface, caves, collision or entity population in memory. Larger universe scale increases catalog/storage requirements; resident memory should primarily depend on active regions and configured detail budgets.
 

docs/design/survival-pressure-and-recovery.md

@@ -1,6 +1,6 @@
 # Survival, pressure, docking, and salvage design contract
 
-This document turns the desired SS13 and Barotrauma-like mechanical direction into first-party rules. These are design references, not a request to copy their art, names, maps, code, or other protected content.
+[HELLION is the primary gameplay and mechanics baseline](hellion-baseline.md): aim for as faithful a remake as practical before layering mechanics from SS13, Barotrauma and other references. The independently authored rules below are Frontier design proposals and constraints; they do not establish HELLION behavior or completed parity. Where a rule may differ from the baseline, record the difference and seek an explicit design decision rather than assume equivalence. No reference grants rights to copy art, names, maps, code, or other protected content.
 
 ## Damage should create work, not erase play
 

docs/development/FIRST_PLAYABLE_HANDOFF.md

@@ -2,7 +2,7 @@
 
 ## Status and owner decisions
 
-The **cooperative first playable source prototype is implemented and verified on Windows**. The owner explicitly requires shared multiplayer and restart persistence. The priority is environmental extraction → portable container → transport/unload → refine → physical component → recycle/reuse. Do not reopen this scope question. See [acceptance evidence](first-playable-acceptance.md) and [launch instructions](first-playable-running.md).
+The **cooperative first playable source prototype is implemented and verified on Windows**. The owner explicitly requires shared multiplayer and restart persistence. The completed route is environmental extraction → portable container → transport/unload → refine → physical component → recycle/reuse. Preserve that milestone's historical acceptance scope. The current project-wide direction is the [HELLION gameplay and mechanics baseline](../design/hellion-baseline.md), followed by additions from other games; the existing route is one bounded foundation and does not establish baseline parity. See [acceptance evidence](first-playable-acceptance.md) and [launch instructions](first-playable-running.md).
 
 This is a bounded development prototype, not the full long-term game or a Steam distribution release. Terrain excavation follows this loop. Civ13-informed civilization progression remains a later update.
 

docs/development/civilization-station-capability-parity.md

@@ -2,6 +2,8 @@
 
 Owner direction (2026-10-11, America/New_York): almost everything a player can do in Civ13 and Space Station 13 should eventually be possible in Frontier Systems. This is a long-term gameplay capability milestone family, not a claim of current implementation or a single feature PR. Preserve the current basic-gameplay/tutorial priorities.
 
+The project-wide first priority is the [HELLION gameplay and mechanics baseline](../design/hellion-baseline.md), with as faithful a remake as practical before layering these broader Civ13/SS13 capabilities. This document remains a long-term extension roadmap; its matrix does not measure HELLION coverage or establish current parity.
+
 ## Target and coverage
 
 Track player capabilities and their outcomes, not identical controls, names, assets or internal code. Aim for broad coverage of both civilization progression and station life; record every gap and any proposed exclusion explicitly. Do not silently narrow this direction to engineering alone. Features may use Frontier's own design while preserving comparable player agency and emergent combinations.
@@ -25,7 +27,7 @@ The first bounded research slice is the [foundational capability matrix v1](foun
 
 ## Milestone sequence and acceptance
 
-1. Build the research matrix and coverage baseline, starting with Civ13 and a pinned owner-relevant SS13 variant. Prioritize ordinary basic actions and independently authored requirements.
+1. For this later extension, build the research matrix and coverage baseline, starting with Civ13 and a pinned owner-relevant SS13 variant. Prioritize ordinary basic actions and independently authored requirements.
 2. Map foundational owners and contracts; implement bounded basic capability gaps before their advanced dependents. Serialize shared authority/schema work and keep each milestone narrow.
 3. Deliver capability clusters with explicit scenarios: authorized success, unavailable prerequisites, stale/foreign rejection, conservation, partial damage/functionality, recovery and multiplayer effects where relevant.
 4. Verify cross-system combinations and emergent use, not only isolated happy paths. Reconcile the matrix against integrated evidence and propose remaining gaps/exclusions to the owner through Coordinator.

docs/development/first-playable-milestone.md

@@ -28,6 +28,8 @@ Two invite slots and periodic/manual checkpoints are the current operational mod
 
 ## Next milestones
 
-First collect two-player feedback and measure the active route. [Equipment fabrication and salvage](equipment-fabrication-milestone.md) now completes craftable carriers/tools. [Sustained hand-tool extraction](sustained-extraction-milestone.md) and [modular powered resource machinery](modular-resource-machinery-milestone.md) are now implemented. The Take On Mars style construction extension includes hand-built printers, expansion modules, portable sockets, deployable generators/extractors and cable/router grids. Terrain excavation follows placement feedback and collision authority improvements. Improve transport movement authority, persistence guarantees and distribution readiness as audience grows.
+The [HELLION baseline](../design/hellion-baseline.md) now sets the project-wide gameplay and mechanics target. The achieved mining loop below is a bounded foundation, not evidence of HELLION parity. Prioritize research and implementation gaps toward that baseline before layering other games' mechanics; retain the earlier milestone record and its actual acceptance scope.
+
+For the existing route, collect two-player feedback and measure it. [Equipment fabrication and salvage](equipment-fabrication-milestone.md) now completes craftable carriers/tools. [Sustained hand-tool extraction](sustained-extraction-milestone.md) and [modular powered resource machinery](modular-resource-machinery-milestone.md) are now implemented. The Take On Mars style construction extension includes hand-built printers, expansion modules, portable sockets, deployable generators/extractors and cable/router grids. Terrain excavation follows placement feedback and collision authority improvements. Improve transport movement authority, persistence guarantees and distribution readiness as audience grows.
 
 [Planet-start civilization progression](../design/civilization-to-space-progression.md), informed by the owner's Civ13 reference, is a later update. Full chemistry/medicine, atmospheric survival, modular colonies/ships, procedural planets, away missions, platform chat/voice, LLM automation and broad roleplay remain long-term work. Optional VR is not required for this first playable route.

docs/research/README.md

@@ -23,7 +23,7 @@ The manifest remains the shared provenance registry required by AGENTS.md. An ex
 
 ## Scope and research queue
 
-Keep each pass bounded to one project decision and a practical way to disprove it.
+[HELLION is the primary gameplay and mechanics baseline](../design/hellion-baseline.md). Research its observable gameplay first, record exact versions and evidence limits, and map independently authored requirements and gaps before treating another game's mechanics as an extension. Keep each pass bounded to one project decision and a practical way to disprove it.
 
 | Topic | Bounded next question | Consult existing work first |
 | --- | --- | --- |

docs/research/reference-manifest.csv

@@ -21,3 +21,4 @@ Godot,https://docs.godotengine.org/en/4.7/tutorials/3d/occlusion_culling.html,Me
 Godot,https://docs.godotengine.org/en/4.7/classes/class_multimesh.html,Class description: spatial grouping AABB and per-object light limit,4.7 class documentation; mutable; no documentation commit captured,,2026-10-25,Official documentation reference; no code or creative asset reuse.,Instanced drawing trades per-object submission for group visibility and lighting constraints.,R-001 / E-001: defer spatial MultiMesh experiment until resource-sharing results show a remaining bottleneck.,Independent summary and links only; no implementation or benchmark reproduced.
 AMD GPUOpen,https://gpuopen.com/learn/rdna-performance-guide/,RDNA Performance Guide: Command buffers; Pipeline state objects; Barriers; Memory,Mutable guide with RDNA 3 updates; exact latest update unverified,2023-03-22,2026-10-25,Vendor documentation reference; no code or creative asset reuse.,Low-level submission state barrier and memory costs need API/hardware context.,R-001: use vendor guidance to form a measured question; Godot owns low-level renderer work.,Independent summary and links only; AMD/RDNA guidance is not measured RTX or whole-game performance.
 Godot,https://godotengine.org/article/introducing-reverse-z/,Introducing Reverse Z; introduction and shader compatibility discussion,Historical 4.3 introduction article by Clay John,2024-04-29,2026-10-25,Official article reference; no code or creative asset reuse.,Godot introduced reverse-Z in 4.3 with compatibility implications for some custom shaders.,R-001: do not propose existing engine depth behavior as new Frontier work.,Independent summary and link only; historical article flags that later documentation supersedes old details.
+HELLION,https://steamcommunity.com/app/588210,Steam community official game description; Steam store About This Game,Public descriptive pages; mutable; no game build or mechanics inventory reviewed,,2026-10-29,Third-party proprietary game; no code or creative asset reuse rights established.,Stranded survivors explore derelict ships and stations and seek air fuel and equipment; store describes multiplayer space-survival simulation.,Primary Frontier gameplay/mechanics baseline; map observed version-specific behavior to independent requirements and acceptance before extensions.,Description-only reference; no game code assets branding UI text or media copied. No official affiliation or implemented parity claimed.