SN2SurvivalTweaks

SN2SurvivalTweaks

Dial Subnautica 2's survival pressure to taste. A lightweight UE4SS Lua mod with five independent sliders — oxygen, hunger, thirst, max health, and damage taken — all configurable in-game via SN2ModSettings. No `.pak` overrides, no save-file edits.

Every slider is "bigger number = easier", so it's impossible to make the game harder by accident — set anything to `1` and that aspect stays vanilla.

What it does

Oxygen Lasts Longer: 1–10× Oxygen drains N× slower underwater (also extends the grace period once your tank hits empty).

Food Lasts Longer: 1–10× Hunger builds N× slower.

Water Lasts Longer: 1–10× Thirst builds N× slower.

Max Health: 1–10×  N× bigger health pool. (Heal up to fill the larger bar.)

Damage Taken Reduced: 1–10× Take 1/N damage from all sources — 10× ≈ near-invincible.

Each has its own enable toggle, plus a debug-logging toggle.

Single-player / host only

This mod changes Gameplay Ability System attributes, which are server-authoritative. It works perfectly in single-player and for the host of a co-op session, but joining players won't see the effect on their own stats. No crashes — it just won't apply for non-host clients.

Requirements

1. UE4SS for Subnautica 2 — (https://www.nexusmods.com/subnautica2/mods/36) / (https://github.com/Subnautica2Modding/Subnautica2-UE4SS)

2. SN2ModSettings — (https://www.nexusmods.com/subnautica2/mods/20) — provides the in-game slider UI.

Installation

1. Make sure UE4SS is installed (the loader `dwmapi.dll` sits next to `Subnautica2-Win64-Shipping.exe`, with the `ue4ss/` folder beside it).

2. Extract this archive so the `SN2SurvivalTweaks/` folder lands in:

<game>\Subnautica2\Binaries\Win64\ue4ss\Mods\

3. Add this line to `ue4ss\Mods\mods.txt` (anywhere):

SN2SurvivalTweaks : 1

This makes the mod load before SN2ModSettings so it shows up in the settings UI on first launch. (If you skip this, just restart the game once and it'll appear.)

4. Launch, open Settings → Mods → Survival Tweaks, and set your sliders.

Configuration

Open Settings → Mods → Survival Tweaks in-game and move the sliders — changes apply within ~1–2 seconds, live, no restart needed. Values persist in `ue4ss\Mods\SN2ModSettings\saved\SN2SurvivalTweaks.lua`.

How it works (technical)

Subnautica 2's survival system is built on Unreal's Gameplay Ability System (GAS). Targets verified from a UE4SS object/header dump:

Food / Water  `UWESurvivalAttributeSet. StarvationRateScalar` / `DehydrationRateScalar` | Direct `FGameplayAttributeData` write (`BaseValue` + `CurrentValue` = vanilla / N). |

Oxygen  `SN2BreathingCalc. SN2BreathingOxygenPerSecond`, `SN2SuffocateCalc. OxygenConsumptionPerSec(+BelowNominalDepth)` | Calc-class CDO floats scaled by 1/N. (`SuffocationRateScalar` is also scaled, but that only governs damage after O₂ is empty — normal depletion lives on the calc CDOs.) |

Max Health `UWEHealthSetComponent:SetMaxHealth()` | Proper setter UFunction (applies a GameplayEffect internally). |

Damage Taken `UWEHealthSetComponent:SetDamageMultiplier(1/N)` | Proper setter UFunction. |

Health is applied only to the local player pawn's component (every creature has a health component too — we match by owner so enemies aren't buffed). Each value's vanilla base is snapshotted once, so sliding a multiplier always recomputes from the true baseline and never compounds. A 1 Hz loop re-asserts the direct writes (self-healing against GAS recomputation) and reacts to slider changes.

Credits

- UE4SS — ported for Subnautica 2 by the (https://github.com/Subnautica2Modding/Subnautica2-UE4SS) group.

- SN2ModSettings by (https://github.com/Just-Chaldea/SN2-ModSettings) — the in-game slider UI.

- ConfigManager pattern adapted from Capacity & QuickBar Tweaks by (https://www.nexusmods.com/subnautica2/mods/252).

License

MIT — see (./LICENSE).

Changelog

### 1. 0. 0

- Initial release: oxygen, food, water, max health, and damage-taken multipliers (1–10× each), with SN2ModSettings sliders and per-aspect toggles.