diff --git a/Core/CmdLine.cpp b/Core/CmdLine.cpp
index 34651fb05e..45a1fba82a 100644
--- a/Core/CmdLine.cpp
+++ b/Core/CmdLine.cpp
@@ -189,7 +189,7 @@ static const CommandLineParam g_autoParams[] = {
 	{POFF(fullscreen), CmdParamType::BoolInverse, "windowed", '\0', "Force windowed mode", CmdLineMode::Application},
 	{POFF(startScreen), CmdParamType::String, "start-screen", '\0', "Start on a specific screen (e.g. 'gamesettings', 'touchscreentest')", CmdLineMode::Application},
 	{POFF(escapeExit), CmdParamType::Bool, "escape-exit", '\0', "Escape key exits the application", CmdLineMode::Application},
-	{POFF(gameWindow), CmdParamType::Bool, "game-window", '\0', "Show the game in a second window, for testing multiple outputs (SDL, Metal only)", CmdLineMode::Application},
+	{POFF(gameWindow), CmdParamType::Bool, "game-window", '\0', "Show the game in a second window, for testing multiple outputs (Vulkan, or Metal on Mac)", CmdLineMode::Application},
 	{POFF(pauseMenuExit), CmdParamType::Bool, "pause-menu-exit", '\0', "Exit the application when the game ends, instead of returning to the menu", CmdLineMode::Application},
 	{POFF(appendConfig), CmdParamType::String, "appendconfig", '\0', "Merge config FILE into the current configuration"},
 	{POFF(root), CmdParamType::String, "root", 'r', "Mount directory as the root of host0:/."},
diff --git a/SDL/SDLMain.cpp b/SDL/SDLMain.cpp
index 594fcd34e0..a808a98ef3 100644
--- a/SDL/SDLMain.cpp
+++ b/SDL/SDLMain.cpp
@@ -1442,7 +1442,9 @@ void UpdateCursor() {
 	SDL_SetCursor(g_builtinCursors[(int)curCursor]);
 }
 
-// --game-window: a second window showing just the game, for testing multiple outputs.
+// --game-window: a second window showing just the game. For now it's only a way to test multiple outputs on
+// the desktop, standing in for a TV over AirPlay. Later, real multi-window support (like ImGui's multi-viewports)
+// will take this over.
 static SDL_Window *g_gameWindow = nullptr;
 static int g_gameOutputId = 0;
 
diff --git a/Windows/MainWindow.cpp b/Windows/MainWindow.cpp
index 966f84dfec..aa78f1f203 100644
--- a/Windows/MainWindow.cpp
+++ b/Windows/MainWindow.cpp
@@ -61,6 +61,8 @@
 #include "Windows/Debugger/Debugger_MemoryDlg.h"
 
 #include "Common/GPU/GraphicsContext.h"
+#include "Common/GPU/thin3d.h"
+#include "Common/SysError.h"
 
 #include "Windows/main.h"
 #include "Windows/DinputDevice.h"
@@ -1348,4 +1350,95 @@ namespace MainWindow {
 		PostMessage(hwndMain, WM_USER_RUN_CALLBACK, reinterpret_cast<WPARAM>(callback), reinterpret_cast<LPARAM>(userdata));
 	}
 
+	// --game-window: a second window showing just the game. For now it's only a way to test multiple outputs on
+	// the desktop, standing in for a TV over AirPlay. Later, real multi-window support (like ImGui's multi-viewports)
+	// will take over these pieces: the window class, the input forwarding and the output lifetime.
+	static HWND hwndGame;
+	static int gameOutputId;
+
+	static LRESULT CALLBACK GameWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
+		switch (message) {
+		case WM_SIZE:
+			if (gameOutputId != 0 && wParam != SIZE_MINIMIZED) {
+				Native_ResizeOutput(gameOutputId, LOWORD(lParam), HIWORD(lParam));
+			}
+			return 0;
+
+		case WM_CLOSE:
+			// The window has to outlive the swapchain, so it stays until we quit.
+			Native_RemoveOutput(gameOutputId);
+			ShowWindow(hWnd, SW_HIDE);
+			return 0;
+
+		case WM_ACTIVATE:
+			if (wParam == WA_ACTIVE || wParam == WA_CLICKACTIVE) {
+				WindowsRawInput::GainFocus();
+				g_InputManager.GainFocus();
+			} else {
+				WindowsRawInput::LoseFocus();
+				g_InputManager.LoseFocus();
+			}
+			return 0;
+
+		case WM_INPUT:
+		{
+			// Keys still go to the emulator. The mouse would get main window coordinates, so it's left out.
+			RAWINPUTHEADER header;
+			UINT size = sizeof(header);
+			if (GetRawInputData((HRAWINPUT)lParam, RID_HEADER, &header, &size, sizeof(RAWINPUTHEADER)) != (UINT)-1 && header.dwType == RIM_TYPEKEYBOARD) {
+				return WindowsRawInput::Process(hWnd, wParam, lParam);
+			}
+			return DefWindowProc(hWnd, message, wParam, lParam);
+		}
+
+		case WM_CHAR:
+			return WindowsRawInput::ProcessChar(hWnd, wParam, lParam);
+
+		default:
+			return DefWindowProc(hWnd, message, wParam, lParam);
+		}
+	}
+
+	void CreateGameWindow() {
+		if ((GPUBackend)g_Config.iGPUBackend != GPUBackend::VULKAN) {
+			ERROR_LOG(Log::System, "--game-window needs Vulkan");
+			return;
+		}
+
+		static constexpr const wchar_t *szGameWindowClass = L"PPSSPPGameWnd";
+		WNDCLASSEX wcex{};
+		wcex.cbSize = sizeof(WNDCLASSEX);
+		wcex.lpfnWndProc = (WNDPROC)GameWndProc;
+		wcex.hInstance = hInst;
+		wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
+		wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
+		wcex.lpszClassName = szGameWindowClass;
+		wcex.hIcon = LoadIcon(hInst, (LPCTSTR)IDI_PPSSPP);
+		wcex.hIconSm = (HICON)LoadImage(hInst, (LPCTSTR)IDI_PPSSPP, IMAGE_ICON, 16, 16, LR_SHARED);
+		RegisterClassEx(&wcex);
+
+		RECT rc{ 0, 0, 960, 544 };
+		AdjustWindowRect(&rc, WS_OVERLAPPEDWINDOW, FALSE);
+		// No owner: an owned window is destroyed along with the main window, which can be before the swapchain is.
+		hwndGame = CreateWindowEx(0, szGameWindowClass, L"PPSSPP game", WS_OVERLAPPEDWINDOW,
+			CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.left, rc.bottom - rc.top, NULL, NULL, hInst, NULL);
+		if (!hwndGame) {
+			ERROR_LOG(Log::System, "Error creating the game window: %s", GetLastErrorMsg().c_str());
+			return;
+		}
+
+		RECT client;
+		GetClientRect(hwndGame, &client);
+		Draw::SwapchainDesc desc{};
+		desc.winsys = WINDOWSYSTEM_WIN32;
+		desc.data1 = hInst;
+		desc.data2 = hwndGame;
+		desc.width = client.right - client.left;
+		desc.height = client.bottom - client.top;
+		desc.tag = "GameWindow";
+		gameOutputId = Native_AddOutput(OutputRole::Game, desc);
+
+		ShowWindow(hwndGame, SW_SHOWNOACTIVATE);
+	}
+
 }  // namespace MainWindow
diff --git a/Windows/MainWindow.h b/Windows/MainWindow.h
index d48b0a3724..31035e13a2 100644
--- a/Windows/MainWindow.h
+++ b/Windows/MainWindow.h
@@ -80,6 +80,7 @@ namespace MainWindow
 	void SetWindowSize(int zoom);
 	void RunCallbackInWndProc(void (*callback)(void *window, void *userdata), void *userdata);
 	void SetKeepScreenBright(bool keepBright);
+	void CreateGameWindow();
 
 	bool ConfirmAction(HWND hWnd, bool actionIsReset);
 }
diff --git a/Windows/main.cpp b/Windows/main.cpp
index 6ddb0441d3..91284155e5 100644
--- a/Windows/main.cpp
+++ b/Windows/main.cpp
@@ -1264,6 +1264,10 @@ int WINAPI WinMain(HINSTANCE _hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLin
 	HWND hwndMain = MainWindow::GetHWND();
 	Achievements::InitializeRAIntegration(hwndMain);
 
+	if (cmdLineOptions.gameWindow.value_or(false)) {
+		MainWindow::CreateGameWindow();
+	}
+
 	//initialize custom controls
 	CtrlDisAsmView::init();
 	CtrlMemView::init();