diff --git a/CMakeLists.txt b/CMakeLists.txt
index ad89a0e..45f420f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ endif()
 
 # Add include directories
 include_directories(${CMAKE_SOURCE_DIR}/deps)
-include_directories(SYSTEM ${CMAKE_SOURCE_DIR}/deps/libtcod)
+include_directories(${CMAKE_SOURCE_DIR}/deps/libtcod)
 
 # Python includes: use different paths for Windows vs Linux
 if(MCRF_CROSS_WINDOWS)
@@ -29,7 +29,7 @@ if(MCRF_CROSS_WINDOWS)
     include_directories(${CMAKE_SOURCE_DIR}/deps/cpython/PC)  # For other Windows-specific headers
     # Also include SFML and libtcod Windows headers
     include_directories(${CMAKE_SOURCE_DIR}/__lib_windows/sfml/include)
-    include_directories(SYSTEM ${CMAKE_SOURCE_DIR}/__lib_windows/libtcod/include)
+    include_directories(${CMAKE_SOURCE_DIR}/__lib_windows/libtcod/include)
 else()
     # Native builds (Linux/Windows): use existing Python setup
     include_directories(${CMAKE_SOURCE_DIR}/deps/cpython)
diff --git a/src/PythonObjectCache.cpp b/src/PythonObjectCache.cpp
index 4d3e453..b280eb2 100644
--- a/src/PythonObjectCache.cpp
+++ b/src/PythonObjectCache.cpp
@@ -36,17 +36,15 @@ void PythonObjectCache::registerObject(uint64_t serial, PyObject* weakref) {
 
 PyObject* PythonObjectCache::lookup(uint64_t serial) {
     if (serial == 0) return nullptr;
-
-    // No mutex needed for read - GIL protects PyWeakref_GetRef
+    
+    // No mutex needed for read - GIL protects PyWeakref_GetObject
     auto it = cache.find(serial);
     if (it != cache.end()) {
-        PyObject* obj = nullptr;
-        int result = PyWeakref_GetRef(it->second, &obj);
-        if (result == 1 && obj) {
-            // obj is already a strong reference from PyWeakref_GetRef
+        PyObject* obj = PyWeakref_GetObject(it->second);
+        if (obj && obj != Py_None) {
+            Py_INCREF(obj);
             return obj;
         }
-        // result == 0: dead reference, result == -1: error
     }
     return nullptr;
 }
@@ -64,18 +62,14 @@ void PythonObjectCache::remove(uint64_t serial) {
 
 void PythonObjectCache::cleanup() {
     std::lock_guard<std::mutex> lock(serial_mutex);
-
+    
     auto it = cache.begin();
     while (it != cache.end()) {
-        PyObject* obj = nullptr;
-        int result = PyWeakref_GetRef(it->second, &obj);
-        if (result <= 0) {
-            // Dead reference or error - remove from cache
+        PyObject* obj = PyWeakref_GetObject(it->second);
+        if (!obj || obj == Py_None) {
             Py_DECREF(it->second);
             it = cache.erase(it);
         } else {
-            // Still alive - release the strong reference we obtained
-            Py_DECREF(obj);
             ++it;
         }
     }