Install the BepInEx 6 loader

What makes this package "specially configured"

Installation, step by step

1. Open the game folder

   In Steam: right-click Game Dev Story in your library → Manage → Browse local files. A window opens at the game folder — on the reference machine that is:

   F:\SteamLibrary\steamapps\common\GameDevStory

   Yours may live under C:\Program Files (x86)\Steam\steamapps\common\GameDevStory or another library drive. The folder you want contains GameAssembly.dll and the game's executable — KairoGames.exe on the current Steam build. Keep this window open.

2. Extract the archive — contents, not the folder

   Open BepInEx-Unity_IL2CPP-win-x86-6_0_0-be_785_6abdba4.rar in 7-Zip or WinRAR. Inside is a single top-level folder named BepInEx-Unity_IL2CPP-win-x86-6_0_0-be_785_6abdba4. Enter it, select everything inside it, and extract into the game folder from step 1:

   what you extract (the contents of the archive's top-level folder):
   BepInEx\            ← core, patchers, plugins, unity-libs
   dotnet\             ← the bundled .NET runtime (186 files)
   .doorstop_version   ← "4.5.0"
   changelog.txt
   doorstop_config.ini
   winhttp.dll         ← the injector — must sit NEXT TO KairoGames.exe

   THE #1 INSTALL MISTAKE

   If you drag the archive's folder in instead of its contents, you end up with ...\GameDevStory\BepInEx-Unity_IL2CPP-win-x86-...\winhttp.dll and the loader never runs. The test is simple: winhttp.dll must end up in the same folder as KairoGames.exe. If Windows asks to merge or overwrite folders, say yes.

3. Check the result against the reference

   Your game folder should now look exactly like this (click the screenshot for full size). The five game-owned items — KairoGames_Data, saves, baselib.dll, GameAssembly.dll, KairoGames.exe, UnityCrashHandler32.exe, UnityPlayer.dll — are joined by the six loader items you just extracted.

   CLICK — FULL SIZE

4. First launch — let BepInEx build its interop layer

   Launch the game normally through Steam. The very first modded start does one-time work:

   • Doorstop loads winhttp.dll, which boots BepInEx before the game.
   • The pre-seeded unity-libs\2022.3.62.zip is unpacked locally — this is the step that needs the internet on stock BepInEx, and doesn't here.
   • Cpp2IL + Il2CppInterop read GameAssembly.dll and generate the interop assemblies into BepInEx\interop\. This is the slow part — allow a minute or so; the game window may take noticeably longer than usual to appear. That's normal, and it only happens once (and again after a game update).

   When the title screen appears, quit the game. The loader is now fully baked.

   CONSOLE WINDOW & ANTIVIRUS

   A separate BepInEx console window may open alongside the game depending on the [Logging.Console] setting in the auto-generated BepInEx\config\BepInEx.cfg — either way, everything is also written to BepInEx\LogOutput.log. And because winhttp.dll is a proxy DLL, an overzealous antivirus can quarantine it; if the game starts completely vanilla with no log file, check your AV's quarantine and whitelist the game folder.

5. Verify the first run

   Open the BepInEx folder. Alongside the core, patchers, plugins and unity-libs folders you extracted, the first run has generated cache, config, interop and LogOutput.log:

   CLICK — FULL SIZE

   Inside BepInEx\unity-libs\ you can see the offline trick at work: the shipped 2022.3.62.zip has been unpacked into the full set of Unity engine assemblies — 53 items, no download required:

   CLICK — FULL SIZE

   Open BepInEx\LogOutput.log in Notepad. A healthy first run begins with the BepInEx banner naming this exact build and the game:

   [Message:   BepInEx] BepInEx 6.0.0-be.785 - KairoGames
   ...
   [Info   :   BepInEx] 0 plugins to load

   "0 plugins to load" is correct at this stage — Parts 2 and 3 fill that in.

   ONE HARMLESS WARNING, DOCUMENTED UP FRONT

   You may see [Warning:Il2CppInterop] Class::Init signatures have been exhausted, using a substitute! in the log (and a small ErrorLog.log may exist). This is emitted by BepInEx's own interop runtime while bootstrapping against Unity 2022.3.62, before any plugin loads. It is a known, harmless notice on this engine version — not a fault in your install, and nothing a plugin can produce or remove.