diff --git a/.gitignore b/.gitignore
index a76d193..c59cf68 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,7 @@ ipch/
 *.suo
 *.user
 *.cachefile
+*.sln.cache
 *.vspscc
 *.vssscc
 *.pch
diff --git a/BUILD.md b/BUILD.md
new file mode 100644
index 0000000..ff94f13
--- /dev/null
+++ b/BUILD.md
@@ -0,0 +1,118 @@
+# Building Red Planet (v4.10, Win32)
+
+This is the Win32 source for the pod-racing game **Red Planet**, built on the
+in-house **MUNGA** engine and its **L4** (Win32 / DirectX 9) platform layer.
+The code targets the Visual Studio 2005/2008 era and the legacy DirectX SDK.
+
+---
+
+## 1. Requirements
+
+You must supply the toolchain — none of it is checked into this repo.
+
+| Component | Required version | Notes |
+|-----------|------------------|-------|
+| **Visual Studio** | 2005 (v8) or 2008 (v9) | Project files are the legacy `.vcproj` format. Modern MSBuild **cannot** build `.vcproj` directly — it needs `VCBuild.exe`, which only ships with VS 2005/2008. A newer VS (2022) can build these but will first *upgrade* the projects to `.vcxproj`. |
+| **DirectX SDK** | March 2009 (June 2010 also works) | Provides `d3d9.lib`, `d3dx9.lib`, `dinput8.lib`, `dxguid.lib`, `dxerr.lib` and headers. |
+| **Windows SDK / Platform SDK** | Matching your VS | Provides `WS2_32.lib`, `dbghelp.lib`, etc. |
+| **`DXSDK_DIR` environment variable** | — | The DirectX SDK installer sets this automatically (includes a trailing backslash). The projects reference the SDK **only** through this variable — see §4. |
+
+### Bundled third-party libraries (already in the repo)
+
+These are committed under [lib/](lib/) and do **not** need to be installed:
+
+- `OpenAL32.lib` — OpenAL audio
+- `libsndfile-1.lib` — sound-file loading
+
+Their headers live in [MUNGA_L4/openal/](MUNGA_L4/openal/) and
+[MUNGA_L4/sndfile.h](MUNGA_L4/sndfile.h). You will still need the matching
+runtime DLLs (`OpenAL32.dll`, `libsndfile-1.dll`) next to the built `.exe` to run it.
+
+---
+
+## 2. Solution / project layout
+
+The solution is [WinTesla.sln](WinTesla.sln). It builds four projects:
+
+| Project | File | Type | Output | Depends on |
+|---------|------|------|--------|------------|
+| **Munga_L4** | [MUNGA_L4/Munga_L4.vcproj](MUNGA_L4/Munga_L4.vcproj) | Static lib | `lib\Munga_l4.lib` | — |
+| **RP_L4** | [RP_L4/RP_L4.vcproj](RP_L4/RP_L4.vcproj) | Application (exe) | `rpl4opt.exe` | Munga_L4 |
+| **RPL4TOOL** | [RP_L4/RPL4TOOL.vcproj](RP_L4/RPL4TOOL.vcproj) | Application (exe) | tool exe | Munga_L4 |
+| **DivLoader** | [DivLoader/DivLoader.vcproj](DivLoader/DivLoader.vcproj) | Static lib | `lib\*.lib` | — |
+
+**Build order:** `Munga_L4` → then `RP_L4` / `RPL4TOOL` (the dependency is
+declared in the solution, so a solution-level build resolves it automatically).
+
+`RP_L4` is the game itself. Its release output is **`rpl4opt.exe`**
+(subsystem: Windows GUI).
+
+### VS2008 project variants
+
+Each of the three main projects also ships a `... VS2008.vcproj` variant
+(format 9.00) alongside the original 8.00 files:
+
+- `MUNGA_L4/Munga_L4 VS2008.vcproj`
+- `RP_L4/RP_L4 VS2008.vcproj`
+- `RP_L4/RPL4TOOL VS2008.vcproj`
+
+The `.sln` references the **8.00** files. If you open in VS 2008, either let it
+upgrade the 8.00 projects, or repoint the solution at the `VS2008` variants.
+
+---
+
+## 3. Build steps
+
+1. Install VS 2005/2008 (with the C++ workload) and the DirectX SDK.
+   Confirm the SDK set `DXSDK_DIR`:
+   ```powershell
+   echo $env:DXSDK_DIR
+   ```
+2. Open `WinTesla.sln` in Visual Studio.
+   - If prompted to upgrade the projects (newer VS), accept — this rewrites the
+     `.vcproj` files to `.vcxproj`. Keep those changes on a branch.
+3. Select a configuration: **Debug | Win32** or **Release | Win32**.
+   (`x64` is not configured — this is a 32-bit build.)
+4. Build the solution (`Ctrl+Shift+B`). `Munga_l4.lib` is produced first into
+   `lib\`, then the executables link against it.
+
+### Command-line build (only with VS 2005/2008 installed)
+
+```powershell
+# From a "Visual Studio 2008 Command Prompt":
+vcbuild WinTesla.sln "Release|Win32"
+```
+> Do **not** use `C:\Windows\Microsoft.NET\Framework\...\MSBuild.exe` on this
+> solution — it fails with `MSB3428: Could not load the Visual C++ component
+> "VCBuild.exe"` because the legacy C++ toolset is not present.
+
+---
+
+## 4. DirectX SDK path (no longer hardcoded)
+
+Originally `Munga_L4.vcproj` and `RP_L4.vcproj` hardcoded the absolute path
+`C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\...`. These have been
+changed to use the standard installer-provided variable, matching what the
+VS2008 variants already did:
+
+- Include dir → `"$(DXSDK_DIR)Include"`
+- Library dir → `"$(DXSDK_DIR)Lib\x86"`
+
+So any DirectX SDK version installed to any location will work, as long as
+`DXSDK_DIR` is set. If you build in an environment where it is not set, either
+set it manually or pass it to the build, e.g.:
+
+```powershell
+$env:DXSDK_DIR = "C:\DXSDK\"   # note the trailing backslash
+```
+
+---
+
+## 5. Known caveats
+
+- **32-bit only.** No `x64` configuration exists.
+- **`Remote Debug|Win32`** configuration is present but is a debugging target,
+  not a normal build config.
+- Requires the OpenAL and libsndfile **runtime DLLs** at run time (see §1).
+- See [docs/BUILD-NOTES.md](docs/BUILD-NOTES.md) for the repository cleanup
+  history, orphaned files, and the full findings behind this document.
diff --git a/MUNGA_L4/Munga_L4.vcproj b/MUNGA_L4/Munga_L4.vcproj
index 332ea5e..ddd0c88 100644
--- a/MUNGA_L4/Munga_L4.vcproj
+++ b/MUNGA_L4/Munga_L4.vcproj
@@ -40,7 +40,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
@@ -62,7 +62,7 @@
 			<Tool
 				Name="VCLibrarianTool"
 				AdditionalDependencies="OpenAL32.lib D3D9.lib D3DX9.lib DXERR.lib"
-				AdditionalLibraryDirectories="..\lib;&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;"
+				AdditionalLibraryDirectories="..\lib;&quot;$(DXSDK_DIR)Lib\x86&quot;"
 			/>
 			<Tool
 				Name="VCALinkTool"
@@ -111,7 +111,7 @@
 				FavorSizeOrSpeed="1"
 				EnableFiberSafeOptimizations="true"
 				WholeProgramOptimization="true"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="false"
 				BasicRuntimeChecks="0"
@@ -133,7 +133,7 @@
 			<Tool
 				Name="VCLibrarianTool"
 				AdditionalDependencies="OpenAL32.lib D3D9.lib D3DX9.lib  DXERR.lib"
-				AdditionalLibraryDirectories="..\lib;&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;"
+				AdditionalLibraryDirectories="..\lib;&quot;$(DXSDK_DIR)Lib\x86&quot;"
 			/>
 			<Tool
 				Name="VCALinkTool"
@@ -177,7 +177,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
@@ -199,7 +199,7 @@
 			<Tool
 				Name="VCLibrarianTool"
 				AdditionalDependencies="OpenAL32.lib D3D9.lib D3DX9.lib DXERR.lib"
-				AdditionalLibraryDirectories="..\lib;&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;"
+				AdditionalLibraryDirectories="..\lib;&quot;$(DXSDK_DIR)Lib\x86&quot;"
 			/>
 			<Tool
 				Name="VCALinkTool"
diff --git a/RP_L4/RP_L4.vcproj b/RP_L4/RP_L4.vcproj
index 5956915..ad56ce9 100644
--- a/RP_L4/RP_L4.vcproj
+++ b/RP_L4/RP_L4.vcproj
@@ -44,7 +44,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				FavorSizeOrSpeed="0"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
@@ -72,7 +72,7 @@
 				ShowProgress="0"
 				OutputFile="$(OutDir)\rpl4opt.exe"
 				LinkIncremental="2"
-				AdditionalLibraryDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;;..\lib"
+				AdditionalLibraryDirectories="&quot;$(DXSDK_DIR)Lib\x86&quot;;..\lib"
 				IgnoreAllDefaultLibraries="false"
 				GenerateDebugInformation="true"
 				SubSystem="2"
@@ -134,7 +134,7 @@
 				FavorSizeOrSpeed="1"
 				EnableFiberSafeOptimizations="true"
 				WholeProgramOptimization="true"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="false"
 				ExceptionHandling="1"
@@ -163,7 +163,7 @@
 				ShowProgress="1"
 				OutputFile="$(OutDir)\rpl4opt.exe"
 				LinkIncremental="2"
-				AdditionalLibraryDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;;..\lib"
+				AdditionalLibraryDirectories="&quot;$(DXSDK_DIR)Lib\x86&quot;;..\lib"
 				GenerateDebugInformation="false"
 				SubSystem="2"
 				OptimizeReferences="2"
@@ -222,7 +222,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				FavorSizeOrSpeed="0"
-				AdditionalIncludeDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include&quot;"
+				AdditionalIncludeDirectories="&quot;$(DXSDK_DIR)Include&quot;"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_CRT_SECURE_NO_DEPRECATE"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
@@ -250,7 +250,7 @@
 				ShowProgress="1"
 				OutputFile="$(OutDir)\rpl4opt.exe"
 				LinkIncremental="2"
-				AdditionalLibraryDirectories="&quot;C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86&quot;;..\lib"
+				AdditionalLibraryDirectories="&quot;$(DXSDK_DIR)Lib\x86&quot;;..\lib"
 				IgnoreAllDefaultLibraries="false"
 				GenerateDebugInformation="true"
 				SubSystem="2"
diff --git a/WinTesla.sln b/WinTesla.sln
index a4c06f2..ba4fdbc 100644
--- a/WinTesla.sln
+++ b/WinTesla.sln
@@ -9,15 +9,6 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "RP_L4", "RP_L4\RP_L4.vcproj
 		{F988B198-A386-40DD-A50E-9A5CE17A92A5} = {F988B198-A386-40DD-A50E-9A5CE17A92A5}
 	EndProjectSection
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "BT410_L4", "BT410_L4\BT410_L4.vcproj", "{3D11EC2A-78C8-4138-AABC-5597846A30F9}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-	ProjectSection(ProjectDependencies) = postProject
-		{F988B198-A386-40DD-A50E-9A5CE17A92A5} = {F988B198-A386-40DD-A50E-9A5CE17A92A5}
-	EndProjectSection
-EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Munga_L4", "MUNGA_L4\Munga_L4.vcproj", "{F988B198-A386-40DD-A50E-9A5CE17A92A5}"
 	ProjectSection(WebsiteProperties) = preProject
 		Debug.AspNetCompiler.Debug = "True"
@@ -33,42 +24,12 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "RPL4TOOL", "RP_L4\RPL4TOOL.
 		{F988B198-A386-40DD-A50E-9A5CE17A92A5} = {F988B198-A386-40DD-A50E-9A5CE17A92A5}
 	EndProjectSection
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "TextureExp", "TextureExp\TextureExp.vcproj", "{E5595E6E-4D04-4114-91A2-0E839698262C}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "MeshExp", "MeshExp\MeshExp.vcproj", "{17BBD54E-1011-45B4-B53D-CDB0588CEF23}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "DivLoader", "DivLoader\DivLoader.vcproj", "{2742FFCF-E94C-4202-BB0E-36D86CD04A09}"
 	ProjectSection(WebsiteProperties) = preProject
 		Debug.AspNetCompiler.Debug = "True"
 		Release.AspNetCompiler.Debug = "False"
 	EndProjectSection
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "SphereExp", "SphereExp\SphereExp.vcproj", "{8FFCD624-4B77-4FE7-9226-642389E31420}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "DetailExp", "DetailExp\DetailExp.vcproj", "{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "MatReplaceExp", "MatReplaceExp\MatReplaceExp.vcproj", "{F6DC05B7-882E-4C10-8462-314EC9BC7759}"
-	ProjectSection(WebsiteProperties) = preProject
-		Debug.AspNetCompiler.Debug = "True"
-		Release.AspNetCompiler.Debug = "False"
-	EndProjectSection
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Win32 = Debug|Win32
@@ -82,11 +43,6 @@ Global
 		{01B740F7-5D4E-4E42-893F-CE018E5EE785}.Release|Win32.Build.0 = Release|Win32
 		{01B740F7-5D4E-4E42-893F-CE018E5EE785}.Remote Debug|Win32.ActiveCfg = Remote Debug|Win32
 		{01B740F7-5D4E-4E42-893F-CE018E5EE785}.Remote Debug|Win32.Build.0 = Remote Debug|Win32
-		{3D11EC2A-78C8-4138-AABC-5597846A30F9}.Debug|Win32.ActiveCfg = Debug|Win32
-		{3D11EC2A-78C8-4138-AABC-5597846A30F9}.Debug|Win32.Build.0 = Debug|Win32
-		{3D11EC2A-78C8-4138-AABC-5597846A30F9}.Release|Win32.ActiveCfg = Release|Win32
-		{3D11EC2A-78C8-4138-AABC-5597846A30F9}.Release|Win32.Build.0 = Release|Win32
-		{3D11EC2A-78C8-4138-AABC-5597846A30F9}.Remote Debug|Win32.ActiveCfg = Debug|Win32
 		{F988B198-A386-40DD-A50E-9A5CE17A92A5}.Debug|Win32.ActiveCfg = Debug|Win32
 		{F988B198-A386-40DD-A50E-9A5CE17A92A5}.Debug|Win32.Build.0 = Debug|Win32
 		{F988B198-A386-40DD-A50E-9A5CE17A92A5}.Release|Win32.ActiveCfg = Release|Win32
@@ -98,42 +54,12 @@ Global
 		{11BDE691-E0D7-443E-A5AF-87B35B8EEAEE}.Release|Win32.ActiveCfg = Release|Win32
 		{11BDE691-E0D7-443E-A5AF-87B35B8EEAEE}.Release|Win32.Build.0 = Release|Win32
 		{11BDE691-E0D7-443E-A5AF-87B35B8EEAEE}.Remote Debug|Win32.ActiveCfg = Remote Debug|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Debug|Win32.ActiveCfg = Debug|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Debug|Win32.Build.0 = Debug|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Release|Win32.ActiveCfg = Release|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Release|Win32.Build.0 = Release|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Remote Debug|Win32.ActiveCfg = Debug|Win32
-		{E5595E6E-4D04-4114-91A2-0E839698262C}.Remote Debug|Win32.Build.0 = Debug|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Debug|Win32.ActiveCfg = Debug|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Debug|Win32.Build.0 = Debug|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Release|Win32.ActiveCfg = Release|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Release|Win32.Build.0 = Release|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Remote Debug|Win32.ActiveCfg = Debug|Win32
-		{17BBD54E-1011-45B4-B53D-CDB0588CEF23}.Remote Debug|Win32.Build.0 = Debug|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Debug|Win32.ActiveCfg = Debug|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Debug|Win32.Build.0 = Debug|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Release|Win32.ActiveCfg = Release|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Release|Win32.Build.0 = Release|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Remote Debug|Win32.ActiveCfg = Debug|Win32
 		{2742FFCF-E94C-4202-BB0E-36D86CD04A09}.Remote Debug|Win32.Build.0 = Debug|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Debug|Win32.ActiveCfg = Debug|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Debug|Win32.Build.0 = Debug|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Release|Win32.ActiveCfg = Release|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Release|Win32.Build.0 = Release|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Remote Debug|Win32.ActiveCfg = Debug|Win32
-		{8FFCD624-4B77-4FE7-9226-642389E31420}.Remote Debug|Win32.Build.0 = Debug|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Debug|Win32.ActiveCfg = Debug|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Debug|Win32.Build.0 = Debug|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Release|Win32.ActiveCfg = Release|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Release|Win32.Build.0 = Release|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Remote Debug|Win32.ActiveCfg = Debug|Win32
-		{E22A8051-BD1E-44C9-ACDB-AC813C034EE1}.Remote Debug|Win32.Build.0 = Debug|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Debug|Win32.ActiveCfg = Debug|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Debug|Win32.Build.0 = Debug|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Release|Win32.ActiveCfg = Release|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Release|Win32.Build.0 = Release|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Remote Debug|Win32.ActiveCfg = Debug|Win32
-		{F6DC05B7-882E-4C10-8462-314EC9BC7759}.Remote Debug|Win32.Build.0 = Debug|Win32
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/docs/BUILD-NOTES.md b/docs/BUILD-NOTES.md
new file mode 100644
index 0000000..a33de78
--- /dev/null
+++ b/docs/BUILD-NOTES.md
@@ -0,0 +1,143 @@
+# Repository & Build Findings
+
+Notes from the initial git import and build assessment of the Red Planet v4.10
+Win32 source. See [BUILD.md](../BUILD.md) for the practical build instructions;
+this file records *what was found and what was changed*, and why.
+
+---
+
+## 1. What this repository is
+
+- Win32 source for the game **Red Planet v4.10** (string confirmed in
+  `RP_L4/rpl4.log`: `Red Planet v4.10`).
+- Engine: **MUNGA** (`MUNGA/`) — a cross-platform C++ game/sim engine.
+- Platform layer: **MUNGA_L4** (`MUNGA_L4/`) — Win32 + DirectX 9 backend
+  (Direct3D 9, DirectInput 8, OpenAL audio, SOS audio middleware headers).
+- Game code: **RP** (`RP/`) and **RP_L4** (`RP_L4/`).
+- Support projects: **DivLoader** (asset/DIV loader), **Setup1** (installer).
+- ~551 tracked files, ~9 MB.
+
+### Toolchain detected on the import machine
+
+At import time the build machine had **no usable C++ toolchain**:
+
+- No Visual Studio, no `cl.exe`, no `VCBuild.exe`, no `vswhere`.
+- Only .NET Framework `MSBuild.exe` (v2–v4) — which cannot build `.vcproj`.
+- MinGW gcc/g++ (unusable for this MSVC/DirectX codebase).
+- The required **DirectX SDK (March 2009)** was not installed.
+
+A build attempt confirmed the blocker:
+
+```
+error MSB3428: Could not load the Visual C++ component "VCBuild.exe".
+```
+
+Building therefore requires installing VS 2005/2008 + the DirectX SDK
+(the user is sourcing these separately).
+
+---
+
+## 2. Changes made during preparation
+
+### 2.1 Git hygiene (initial import commit)
+
+- Removed stale **Subversion** metadata (`Setup1/.svn/`) that pointed at a dead
+  server (`https://dev.vgcorps.com/svn/WinTesla`).
+- Added [`.gitignore`](../.gitignore) — VS build artifacts, IDE state, `*.log`,
+  OS cruft. This excludes the runtime log `RP_L4/rpl4.log`.
+- Added [`.gitattributes`](../.gitattributes) — normalizes line endings, forces
+  CRLF on Win32 source, marks `.lib/.res/.egg/.rtf` as binary.
+
+### 2.2 Solution cleanup (`WinTesla.sln`)
+
+The original solution referenced **10** projects, but only **4** exist in the
+repo. The 6 dangling references were removed so the solution loads cleanly:
+
+| Removed project | Path referenced | Present? |
+|-----------------|-----------------|----------|
+| BT410_L4 | `BT410_L4\BT410_L4.vcproj` | ❌ missing |
+| TextureExp | `TextureExp\TextureExp.vcproj` | ❌ missing |
+| MeshExp | `MeshExp\MeshExp.vcproj` | ❌ missing |
+| SphereExp | `SphereExp\SphereExp.vcproj` | ❌ missing |
+| DetailExp | `DetailExp\DetailExp.vcproj` | ❌ missing |
+| MatReplaceExp | `MatReplaceExp\MatReplaceExp.vcproj` | ❌ missing |
+
+Remaining (present) projects: **RP_L4, Munga_L4, RPL4TOOL, DivLoader**.
+Their `GlobalSection(ProjectConfigurationPlatforms)` entries were pruned to
+match. `SolutionConfigurationPlatforms` (Debug/Release/Remote Debug | Win32)
+were left unchanged.
+
+> The 6 missing projects appear to be model/texture exporter tools and a sister
+> game project (`BT410` — a different pod title) that live in other
+> repositories. If you obtain them, re-add them to the solution.
+
+### 2.3 DirectX SDK path un-hardcoded
+
+`Munga_L4.vcproj` and `RP_L4.vcproj` (the VS2005 / v8.00 files) hardcoded:
+
+```
+C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Include
+C:\Program Files (x86)\Microsoft DirectX SDK (March 2009)\Lib\x86
+```
+
+Both were replaced (6 occurrences each) with the installer-provided variable,
+matching what the existing `... VS2008.vcproj` variants already used:
+
+```
+$(DXSDK_DIR)Include
+$(DXSDK_DIR)Lib\x86
+```
+
+`DXSDK_DIR` is set by the DirectX SDK installer and ends in a trailing
+backslash, so `$(DXSDK_DIR)Include` resolves correctly.
+
+---
+
+## 3. Project reference data
+
+Collected from the `.vcproj` files for quick reference.
+
+### Configuration types
+- `ConfigurationType="1"` → Application (exe): `RP_L4`, `RPL4TOOL`
+- `ConfigurationType="4"` → Static library: `Munga_L4`, `DivLoader`
+
+### Link dependencies
+- **Munga_L4:** `OpenAL32.lib D3D9.lib D3DX9.lib DXERR.lib`
+- **RP_L4:** `WS2_32.lib Munga_l4.lib dinput8.lib dxguid.lib openal32.lib
+  libsndfile-1.lib d3dx9.lib d3d9.lib dbghelp.lib`
+- **RPL4TOOL:** `Munga_l4.lib libsndfile-1.lib WS2_32.lib dinput8.lib dxguid.lib`
+
+### Preprocessor definitions (RP_L4)
+- Debug: `WIN32;_DEBUG;_WINDOWS;_CRT_SECURE_NO_DEPRECATE`
+- Release: `WIN32;_WINDOWS;_CRT_SECURE_NO_DEPRECATE`
+
+### Character set
+- `Munga_L4`, `RP_L4`, `RPL4TOOL`: `CharacterSet="1"` (Unicode)
+- `DivLoader`: `CharacterSet="2"` (MBCS)
+
+---
+
+## 4. Orphaned / non-build files (informational)
+
+These files are present but are **not referenced by any project**, so they do
+not affect the build. Left in place for historical completeness:
+
+- `MUNGA_L4/JOYSTICK.asm` — MASM source, **not** in any `.vcproj`. No MASM
+  toolchain is required to build. (`L4JOYSTK.h` exists but the `.asm` is unused.)
+- `MUNGA_L4/sos/SOSMAWE.C` and the `sos/bc4`, `sos/wc` header trees — SOS audio
+  middleware for old Borland/Watcom compilers; headers only.
+- `RP_L4/TEST.EGG`, `RP_L4/last.egg` — `.egg` data blobs. `last.egg` is likely
+  runtime-generated ("last loaded"); kept in tracking pending confirmation.
+- `docs/audionotes.rtf` — design notes.
+
+---
+
+## 5. Open questions for the owner
+
+1. Are the 6 removed projects (BT410_L4, *Exp tools) needed here, or do they
+   belong to separate repos?
+2. Is `RP_L4/last.egg` a real asset or generated output? If generated, add it to
+   `.gitignore` and untrack it.
+3. Which VS version is the target going forward — keep VS2005/2008 `.vcproj`, or
+   upgrade to `.vcxproj` for a modern VS + Windows SDK (dropping the legacy
+   DirectX SDK in favor of the Windows SDK's Direct3D)?