subnautica-ii-coop-mod

What problem does it solve?

It solves the challenge of setting up and keeping Subnautica 2 multiplayer gameplay synchronized across players using a BepInEx-based co-op mod, including installation, session setup, and common sync troubleshooting.

Core Features & Use Cases

• Deterministic state synchronization: Keeps gameplay state aligned across clients so actions (like inventory/world updates) don’t drift.
• Adaptive difficulty scaling: Adjusts difficulty to match group size and gameplay conditions.
• Decentralized peer-to-peer networking: Enables co-op without requiring a central server, using NAT punch-through and sync interval controls.
• Shared gameplay options: Supports shared blueprints, shared map pings, and time-of-day synchronization.
• Optional AI narration/lore integration: Hooks into OpenAI/Claude flows for narration and creature lore during co-op.

Quick Start

Install BepInEx 6.0.x, copy the Deep Synergy plugin files into Subnautica 2’s BepInEx/plugins directory, create the required config file at BepInEx/config/synergy_profile.json, then start the host session with /start_server and share the session code with your friends to join using /join_session <session-code>.