diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4a33e2b9..50dbe421 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -59,6 +59,67 @@ jobs:
             -Werror=dev
           cmake --build build -- -k0
 
+  build-with-entropy:
+    name: 'MSVC 4.20 with additional entropy'
+    runs-on: windows-latest
+    strategy:
+      matrix:
+        instance: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - uses: actions/checkout@v4
+      with:
+        repository: itsmattkc/msvc420
+        path: msvc420
+
+    - name: Setup cmake
+      uses: jwlawson/actions-setup-cmake@v2
+      with:
+        # Use minimum supported version
+        cmake-version: '3.15.x'
+
+    - name: Patch MSVC 4.2
+      run: |
+        tools/patch_c2.py msvc420/bin/C2.EXE
+
+    - name: Generate Entropy
+      shell: bash
+      run: |
+        tools/entropy.sh
+
+    - name: Build
+      shell: cmd
+      run: |
+        call .\msvc420\bin\VCVARS32.BAT x86
+        cmake -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo -ISLE_INCLUDE_ENTROPY=ON -G "NMake Makefiles"
+        cmake --build build
+
+    - name: Upload Artifact
+      uses: actions/upload-artifact@main
+      with:
+        name: Win32-Entropy-${{ matrix.instance }}
+        path: |
+          build/CONFIG.EXE
+          build/CONFIG.PDB
+          build/ISLE.EXE
+          build/ISLE.PDB
+          build/LEGO1.DLL
+          build/LEGO1.PDB
+
+  merge-entropy-artifacts:
+    name: 'Merge entropy artifacts'
+    runs-on: ubuntu-latest
+    needs: build-with-entropy
+    steps:
+      - name: Merge Artifacts
+        uses: actions/upload-artifact/merge@v4
+        with:
+          name: Win32-Entropy
+          pattern: Win32-Entropy-*
+          separate-directories: true
+          
   build:
     name: 'MSVC 4.20'
     runs-on: windows-latest
@@ -102,7 +163,7 @@ jobs:
 
   compare:
     name: Compare with master
-    needs: [build, fetch-deps]
+    needs: [build, merge-entropy-artifacts, fetch-deps]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@main
@@ -116,6 +177,11 @@ jobs:
        name: Win32
        path: build
 
+    - uses: actions/download-artifact@main
+      with:
+       name: Win32-Entropy
+       path: build-entropy
+
     - name: Restore cached original binaries
       id: cache-original-binaries
       uses: actions/cache/restore@v4
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 76bdb406..c6b24a35 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -66,6 +66,7 @@ option(ISLE_DECOMP_ASSERT "Assert struct size" ${MSVC_FOR_DECOMP})
 cmake_dependent_option(ISLE_USE_DX5_LIBS "Build with internal DirectX 5 SDK Libraries" ON ISLE_USE_DX5 OFF)
 option(ISLE_BUILD_LEGO1 "Build LEGO1.DLL library" ON)
 option(ISLE_BUILD_BETA10 "Build BETA10.DLL library" OFF)
+option(ISLE_INCLUDE_ENTROPY "Build with entropy.h" OFF)
 
 if(NOT (ISLE_BUILD_LEGO1 OR ISLE_BUILD_BETA10))
   message(FATAL_ERROR "ISLE_BUILD_LEGO1 AND ISLE_BUILD_BETA10 cannot be both disabled")
@@ -585,6 +586,12 @@ if (MSVC_FOR_DECOMP)
     set_property(TARGET isle ${lego1_targets} PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
   endif()
 
+  if (ISLE_INCLUDE_ENTROPY)
+    foreach(tgt IN LISTS lego1_targets beta10_targets)
+      target_compile_options(${tgt} PRIVATE /FI${PROJECT_SOURCE_DIR}/tools/entropy.h)
+    endforeach()
+  endif()
+
   if(TARGET lego1)
     target_link_options(lego1 PRIVATE "/OPT:REF")
     # Equivalent to target_compile_options(... PRIVATE "/MT$<$<CONFIG:Debug>:d>")
diff --git a/tools/entropy.h b/tools/entropy.h
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/tools/entropy.h
@@ -0,0 +1 @@
+
diff --git a/tools/entropy.sh b/tools/entropy.sh
new file mode 100644
index 00000000..397123c2
--- /dev/null
+++ b/tools/entropy.sh
@@ -0,0 +1,31 @@
+#!/bin/bash
+
+# Output file
+OUTPUT_FILE="entropy.h"
+
+# Function to generate a random CamelCase string of given length
+generate_name() {
+    cat /dev/urandom | tr -dc 'a-z' | fold -w "$1" | head -n 1 | sed -E 's/(^|_)([a-z])/\U\2/g'
+}
+
+# Generate a random number of classes (between 1 and 10)
+NUM_CLASSES=$((RANDOM % 10 + 1))
+
+> "$OUTPUT_FILE"  # Clear or create the output file
+
+for ((i=0; i<NUM_CLASSES; i++)); do
+    CLASS_NAME="Class$(generate_name 6)"
+    echo "class $CLASS_NAME {" >> "$OUTPUT_FILE"
+    
+    # Generate a random number of methods (between 1 and 10)
+    NUM_METHODS=$((RANDOM % 10 + 1))
+    for ((j=0; j<NUM_METHODS; j++)); do
+        METHOD_NAME="Function$(generate_name 8)"
+        echo "inline void $METHOD_NAME() {}" >> "$OUTPUT_FILE"
+    done
+    
+    echo "};" >> "$OUTPUT_FILE"
+    echo >> "$OUTPUT_FILE"  # Add an empty line for readability
+done
+
+echo "Generated $NUM_CLASSES classes in $OUTPUT_FILE"