Tutorials ‐ Ripping the entire game - ow-mods/outer-wilds-unity-wiki GitHub Wiki

Requires Outer Wilds Unity Assets and 27.4 GB of free disk space.
If you don't have access to Unity Assets, skip steps 6, 7, and 10.

Download the latest version of AssetRipper.
Scroll down on that page a bit to see the zip files under Assets. You probably want the win_x64 one, assuming you're using Windows.
In View > Settings, change Shader Export Format to Yaml Asset. Leave all other settings at defaults.
Click Save at the bottom to save the settings. You can save the settings to disk if you don't want to have to change this every time you open AssetRipper.
In View > Configuration Files, go to EngineResourceData and select a file with {"DefaultResources":{},"ExtraResources":{}} in it.
You can just create this file yourself in notepad or something, the file name does not matter.
Go to File > Open Folder and select the game folder (e.g. C:\Program Files (x86)\Steam\steamapps\common\Outer Wilds)
Go to Export > Export All Files, select a folder, and click Export Unity Project.
Delete Scripts, Plugins, and Editor in Assets. Delete Packages in ExportedProject.
From Outer Wilds Unity Assets, put Assembly-CSharp, Dlls, Plugins, and Editor into Assets. Put Packages into ExportedProject.
Create a backup of Assets/Shader and Assets/Resources/shaders, as script errors can lead to corruption of shaders.
Open ExportedProject in Unity 2019.4.39f1. The first time opening will take a while (importing makes it take an hour).
The Scenes folder has all the levels of the game. You'll probably want SolarSystem.
If you want to see planets, you have 2 options:
1. Go to Tools > Load All Streaming Bundles or Tools > Streaming Mesh Manager.
  This will show high-quality meshes but not high-quality textures, and does not persist when reloading the scene.
2. Use the unstreamer.
  This will persist when reloading the scene, and can also (optionally) show high-quality textures, at the cost of taking more time.