diff --git a/src/engine/platform/platform.h b/src/engine/platform/platform.h
index ad3ba19..cbc7f93 100644
--- a/src/engine/platform/platform.h
+++ b/src/engine/platform/platform.h
@@ -36,7 +36,7 @@ class Platform {
 #elif defined(__linux__)
   Platform();
 #elif defined(_WIN32)
-  Platform(HINSTANCE hInstance, int nCmdShow);
+  Platform(HINSTANCE instance, int cmd_show);
 #endif
   ~Platform();
 
@@ -127,11 +127,10 @@ class Platform {
 
 #elif defined(_WIN32)
 
-  // Global Variables:
-  HINSTANCE hInst;           // current instance
-  HWND hWnd;
+  HINSTANCE instance_;
+  HWND wnd_;
+  int cmd_show_;
 
-  // Forward declarations of functions included in this code module:
   static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
 #endif
diff --git a/src/engine/platform/platform_win.cc b/src/engine/platform/platform_win.cc
index 00914b0..c299161 100644
--- a/src/engine/platform/platform_win.cc
+++ b/src/engine/platform/platform_win.cc
@@ -8,7 +8,7 @@
 #include "base/log.h"
 // #include "base/vecmath.h"
 // #include "engine/input_event.h"
-// #include "engine/platform/platform_observer.h"
+#include "engine/platform/platform_observer.h"
 
 using namespace base;
 
@@ -16,7 +16,8 @@ namespace eng {
 
 void KaliberMain(Platform* platform);
 
-Platform::Platform(HINSTANCE hInstance, int nCmdShow) : hInst(hInstance) {
+Platform::Platform(HINSTANCE instance, int cmd_show)
+    : instance_(instance), cmd_show_(cmd_show) {
   LOG(0) << "Initializing platform.";
 
   root_path_ = "./";
@@ -33,31 +34,44 @@ Platform::Platform(HINSTANCE hInstance, int nCmdShow) : hInst(hInstance) {
   wcex.lpfnWndProc = WndProc;
   wcex.cbClsExtra = 0;
   wcex.cbWndExtra = 0;
-  wcex.hInstance = hInstance;
-  wcex.hIcon =
-      nullptr;  // LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WINDOWSPROJECT1));
+  wcex.hInstance = instance_;
+  wcex.hIcon = nullptr;
   wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
-  wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
-  wcex.lpszMenuName = nullptr;  // MAKEINTRESOURCEW(IDC_WINDOWSPROJECT1);
-  wcex.lpszClassName = L"szWindowClass";
-  wcex.hIconSm =
-      nullptr;  // LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
-  RegisterClassExW(&wcex);
+  wcex.hbrBackground = nullptr;
+  wcex.lpszMenuName = nullptr;
+  wcex.lpszClassName = L"KaliberWndClass";
+  wcex.hIconSm = nullptr;
+  RegisterClassEx(&wcex);
+}
 
-  hWnd = CreateWindowW(L"szWindowClass", L"kaliber", WS_OVERLAPPEDWINDOW,
-                       CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr,
-                       hInstance, nullptr);
-  CHECK(hWnd);
+void Platform::CreateMainWindow() {
+  wnd_ = CreateWindow(L"KaliberWndClass", L"Kaliber", WS_OVERLAPPEDWINDOW,
+                      CW_USEDEFAULT, 0, 800, 1205, nullptr, nullptr, instance_,
+                      this);
+  CHECK(wnd_);
 
-  ShowWindow(hWnd, nCmdShow);
-  UpdateWindow(hWnd);
+  ShowWindow(wnd_, cmd_show_);
+  UpdateWindow(wnd_);
 }
 
 Platform::~Platform() {
   LOG(0) << "Shutting down platform.";
+  DestroyWindow(wnd_);
 }
 
-void Platform::Update() {}
+void Platform::Update() {
+  DCHECK(!should_exit_);
+
+  MSG msg;
+  while (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE)) {
+    if (msg.message == WM_QUIT) {
+      should_exit_ = true;
+      break;
+    }
+    TranslateMessage(&msg);
+    DispatchMessage(&msg);
+  }
+}
 
 void Platform::Exit() {
   should_exit_ = true;
@@ -72,60 +86,45 @@ void Platform::ShareFile(const std::string& file_name) {}
 void Platform::SetKeepScreenOn(bool keep_screen_on) {}
 
 HINSTANCE Platform::GetInstance() {
-  return hInst;
+  return instance_;
 }
 
 HWND Platform::GetWindow() {
-  return hWnd;
+  return wnd_;
 }
 
-LRESULT CALLBACK Platform::WndProc(HWND hWnd,
+LRESULT CALLBACK Platform::WndProc(HWND wnd,
                                    UINT message,
-                                   WPARAM wParam,
-                                   LPARAM lParam) {
-  // switch (message)
-  // {
-  // case WM_COMMAND:
-  //     {
-  //         int wmId = LOWORD(wParam);
-  //         // Parse the menu selections:
-  //         switch (wmId)
-  //         {
-  //         case IDM_ABOUT:
-  //             DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
-  //             break;
-  //         case IDM_EXIT:
-  //             DestroyWindow(hWnd);
-  //             break;
-  //         default:
-  //             return DefWindowProc(hWnd, message, wParam, lParam);
-  //         }
-  //     }
-  //     break;
-  // case WM_PAINT:
-  //     {
-  //         PAINTSTRUCT ps;
-  //         HDC hdc = BeginPaint(hWnd, &ps);
-  //         // TODO: Add any drawing code that uses hdc here...
-  //         EndPaint(hWnd, &ps);
-  //     }
-  //     break;
-  // case WM_DESTROY:
-  //     PostQuitMessage(0);
-  //     break;
-  // default:
-      return DefWindowProc(hWnd, message, wParam, lParam);
-  // }
-  // return 0;
+                                   WPARAM wparam,
+                                   LPARAM lparam) {
+  auto* platform =
+      reinterpret_cast<Platform*>(GetWindowLongPtr(wnd, GWL_USERDATA));
+
+  switch (message) {
+    case WM_CREATE:
+      SetWindowLongPtr(wnd, GWL_USERDATA,
+                       (LONG_PTR)(((LPCREATESTRUCT)lparam)->lpCreateParams));
+      break;
+    case WM_SIZE:
+      platform->observer_->OnWindowResized(LOWORD(lparam), HIWORD(lparam));
+      break;
+    case WM_DESTROY:
+      platform->observer_->OnWindowDestroyed();
+      PostQuitMessage(0);
+      break;
+    default:
+      return DefWindowProc(wnd, message, wparam, lparam);
+  }
+  return 0;
 }
 
 }  // namespace eng
 
-int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
-                      _In_opt_ HINSTANCE hPrevInstance,
-                      _In_ LPWSTR lpCmdLine,
-                      _In_ int nCmdShow) {
-  eng::Platform platform(hInstance, nCmdShow);
+int WINAPI WinMain(HINSTANCE instance,
+                   HINSTANCE prev_instance,
+                   PSTR cmd_line,
+                   int cmd_show) {
+  eng::Platform platform(instance, cmd_show);
   eng::KaliberMain(&platform);
   return 0;
 }