diff --git a/ISLE/isleapp.cpp b/ISLE/isleapp.cpp
index 10a06a6a..e7c2dda1 100644
--- a/ISLE/isleapp.cpp
+++ b/ISLE/isleapp.cpp
@@ -178,18 +178,14 @@ MxS32 IsleApp::SetupLegoOmni()
 	char mediaPath[256];
 	GetProfileStringA("LEGO Island", "MediaPath", "", mediaPath, sizeof(mediaPath));
 
-	// [library:window] For now, get the underlying Windows HWND to pass into Omni
-	HWND hwnd = (HWND
-	) SDL_GetPointerProperty(SDL_GetWindowProperties(m_windowHandle), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
-
 #ifdef COMPAT_MODE
 	MxS32 failure;
 	{
-		MxOmniCreateParam param(mediaPath, hwnd, m_videoParam, MxOmniCreateFlags());
+		MxOmniCreateParam param(mediaPath, m_windowHandle, m_videoParam, MxOmniCreateFlags());
 		failure = Lego()->Create(param) == FAILURE;
 	}
 #else
-	MxS32 failure = Lego()->Create(MxOmniCreateParam(mediaPath, hwnd, m_videoParam, MxOmniCreateFlags())) == FAILURE;
+	MxS32 failure = Lego()->Create(MxOmniCreateParam(mediaPath, m_windowHandle, m_videoParam, MxOmniCreateFlags())) == FAILURE;
 #endif
 
 	if (!failure) {
@@ -392,12 +388,17 @@ SDL_AppResult SDL_AppEvent(void* appstate, SDL_Event* event)
 		break;
 	}
 
-	// FIXME: use g_userEvent instead of SDL_EVENT_USER
-	if (event->type >= SDL_EVENT_USER && event->type <= SDL_EVENT_LAST - 1) {
+    if (event->user.type == g_LegoSdlEvents.windows_message) {
 		switch (event->user.code) {
 		case WM_ISLE_SETCURSOR:
 			g_isle->SetupCursor((Cursor) (uintptr_t) event->user.data1);
 			break;
+		case WM_QUIT:
+            return SDL_APP_SUCCESS;
+			break;
+        default:
+            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Unknown SDL Windows message: 0x%" SDL_PRIx32, event->user.code);
+            break;
 		}
 	}
 
diff --git a/LEGO1/lego/legoomni/include/legomain.h b/LEGO1/lego/legoomni/include/legomain.h
index c7126f85..a323cdf3 100644
--- a/LEGO1/lego/legoomni/include/legomain.h
+++ b/LEGO1/lego/legoomni/include/legomain.h
@@ -1,8 +1,10 @@
 #ifndef LEGOMAIN_H
 #define LEGOMAIN_H
 
+#include <SDL3/SDL_events.h>
 #include "compat.h"
 #include "lego1_export.h"
+#include "legoutils.h"
 #include "mxdsaction.h"
 #include "mxomni.h"
 
@@ -185,7 +187,14 @@ class LegoOmni : public MxOmni {
 	MxResult StartActionIfUnknown0x13c(MxDSAction& p_dsAction) { return m_unk0x13c ? Start(&p_dsAction) : SUCCESS; }
 	void SetUnknown13c(MxBool p_unk0x13c) { m_unk0x13c = p_unk0x13c; }
 
-	void CloseMainWindow() { PostMessageA(m_windowHandle, WM_CLOSE, 0, 0); }
+	void CloseMainWindow() {
+        SDL_Event event;
+        event.user.type = g_LegoSdlEvents.windows_message;
+        event.user.code = WM_CLOSE;
+        event.user.data1 = NULL;
+        event.user.data2 = NULL;
+        SDL_PushEvent(&event);
+    }
 
 	// SYNTHETIC: LEGO1 0x10058b30
 	// LegoOmni::`scalar deleting destructor'
diff --git a/LEGO1/lego/legoomni/include/legoutils.h b/LEGO1/lego/legoomni/include/legoutils.h
index ef816382..49a87543 100644
--- a/LEGO1/lego/legoomni/include/legoutils.h
+++ b/LEGO1/lego/legoomni/include/legoutils.h
@@ -4,8 +4,10 @@
 #include "actionsfwd.h"
 #include "decomp.h"
 #include "extra.h"
+#include "lego1_export.h"
 #include "mxtypes.h"
 
+#include <SDL3/SDL_stdinc.h>
 #include <windows.h>
 
 #define WM_ISLE_SETCURSOR 0x5400
@@ -13,6 +15,12 @@
 // name verified by BETA10 0x100d4054
 #define DS_NOT_A_STREAM -1
 
+struct LegoSdlEvents {
+    Uint32 windows_message;
+};
+
+LEGO1_EXPORT extern LegoSdlEvents g_LegoSdlEvents;
+
 enum Cursor {
 	e_cursorArrow = 0,
 	e_cursorBusy,
@@ -58,6 +66,7 @@ void PlayCamAnim(LegoPathActor* p_actor, MxBool p_unused, MxU32 p_location, MxBo
 void FUN_1003eda0();
 MxBool RemoveFromCurrentWorld(const MxAtomId& p_atomId, MxS32 p_id);
 void EnableAnimations(MxBool p_enable);
+void InitSdlEvents();
 void SetAppCursor(Cursor p_cursor);
 MxBool FUN_1003ef60();
 MxBool RemoveFromWorld(MxAtomId& p_entityAtom, MxS32 p_entityId, MxAtomId& p_worldAtom, MxS32 p_worldEntityId);
diff --git a/LEGO1/lego/legoomni/src/common/legoutils.cpp b/LEGO1/lego/legoomni/src/common/legoutils.cpp
index 8230f4e2..978aa703 100644
--- a/LEGO1/lego/legoomni/src/common/legoutils.cpp
+++ b/LEGO1/lego/legoomni/src/common/legoutils.cpp
@@ -37,6 +37,8 @@
 #include <string.h>
 #include <vec.h>
 
+LegoSdlEvents g_LegoSdlEvents;
+
 // FUNCTION: LEGO1 0x1003dd70
 // FUNCTION: BETA10 0x100d3410
 LegoROI* PickROI(MxLong p_x, MxLong p_y)
@@ -565,13 +567,20 @@ void EnableAnimations(MxBool p_enable)
 	AnimationManager()->FUN_100604d0(p_enable);
 }
 
+void InitSdlEvents() {
+    static bool initialized = false;
+    if (!initialized) {
+        initialized = true;
+        Uint32 event = SDL_RegisterEvents(1);
+        g_LegoSdlEvents.windows_message = event + 0;
+    }
+}
+
 // FUNCTION: LEGO1 0x1003ef40
 void SetAppCursor(Cursor p_cursor)
 {
-	static Uint32 g_userEvent = SDL_RegisterEvents(1);
-
 	SDL_Event event;
-	event.user.type = g_userEvent;
+	event.user.type = g_LegoSdlEvents.windows_message;
 	event.user.code = WM_ISLE_SETCURSOR;
 	event.user.data1 = (void*) p_cursor;
 	SDL_PushEvent(&event);
diff --git a/LEGO1/lego/legoomni/src/input/legoinputmanager.cpp b/LEGO1/lego/legoomni/src/input/legoinputmanager.cpp
index c18367f5..e90be07d 100644
--- a/LEGO1/lego/legoomni/src/input/legoinputmanager.cpp
+++ b/LEGO1/lego/legoomni/src/input/legoinputmanager.cpp
@@ -518,7 +518,8 @@ MxBool LegoInputManager::FUN_1005cdf0(LegoEventNotificationParam& p_param)
 // FUNCTION: BETA10 0x10089fc5
 void LegoInputManager::StartAutoDragTimer()
 {
-	m_autoDragTimerID = ::SetTimer(LegoOmni::GetInstance()->GetWindowHandle(), 1, m_autoDragTime, NULL);
+    HWND hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+	m_autoDragTimerID = ::SetTimer(hWnd, 1, m_autoDragTime, NULL);
 }
 
 // FUNCTION: LEGO1 0x1005cfd0
@@ -526,7 +527,8 @@ void LegoInputManager::StartAutoDragTimer()
 void LegoInputManager::StopAutoDragTimer()
 {
 	if (m_autoDragTimerID) {
-		::KillTimer(LegoOmni::GetInstance()->GetWindowHandle(), m_autoDragTimerID);
+        HWND hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+		::KillTimer(hWnd, m_autoDragTimerID);
 	}
 }
 
diff --git a/LEGO1/lego/legoomni/src/main/legomain.cpp b/LEGO1/lego/legoomni/src/main/legomain.cpp
index fe7fc015..a83a0989 100644
--- a/LEGO1/lego/legoomni/src/main/legomain.cpp
+++ b/LEGO1/lego/legoomni/src/main/legomain.cpp
@@ -160,6 +160,7 @@ MxResult LegoOmni::Create(MxOmniCreateParam& p_param)
 {
 	MxResult result = FAILURE;
 	AUTOLOCK(m_criticalSection);
+    HWND hWnd = NULL;
 
 	p_param.CreateFlags().CreateObjectFactory(FALSE);
 	p_param.CreateFlags().CreateVideoManager(FALSE);
@@ -191,7 +192,8 @@ MxResult LegoOmni::Create(MxOmniCreateParam& p_param)
 		goto done;
 	}
 
-	if (!(m_inputManager = new LegoInputManager()) || m_inputManager->Create(p_param.GetWindowHandle()) != SUCCESS) {
+    hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+	if (!(m_inputManager = new LegoInputManager()) || m_inputManager->Create(hWnd) != SUCCESS) {
 		delete m_inputManager;
 		m_inputManager = NULL;
 		goto done;
@@ -260,6 +262,8 @@ MxResult LegoOmni::Create(MxOmniCreateParam& p_param)
 	SetAppCursor(e_cursorBusy);
 	m_gameState->SetCurrentAct(LegoGameState::e_act1);
 
+    InitSdlEvents();
+
 	result = SUCCESS;
 
 done:
diff --git a/LEGO1/lego/legoomni/src/video/legovideomanager.cpp b/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
index fb7bd950..d9aa657a 100644
--- a/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
+++ b/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
@@ -85,7 +85,7 @@ MxResult LegoVideoManager::Create(MxVideoParam& p_videoParam, MxU32 p_frequencyM
 	Mx3DPointFloat dirVec(0.0, 0.0, 1.0);
 	Mx3DPointFloat upVec(0.0, 1.0, 0.0);
 	MxMatrix outMatrix;
-	HWND hwnd = MxOmni::GetInstance()->GetWindowHandle();
+	HWND hwnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
 	MxS32 bits = p_videoParam.Flags().Get16Bit() ? 16 : 8;
 
 	if (!p_videoParam.GetPalette()) {
@@ -176,7 +176,7 @@ MxResult LegoVideoManager::Create(MxVideoParam& p_videoParam, MxU32 p_frequencyM
 
 	Lego3DManager::CreateStruct createStruct;
 	memset(&createStruct, 0, sizeof(createStruct));
-	createStruct.m_hWnd = LegoOmni::GetInstance()->GetWindowHandle();
+	createStruct.m_hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
 	createStruct.m_pDirectDraw = m_pDirectDraw;
 	createStruct.m_pFrontBuffer = m_displaySurface->GetDirectDrawSurface1();
 	createStruct.m_pBackBuffer = m_displaySurface->GetDirectDrawSurface2();
diff --git a/LEGO1/omni/include/mxomni.h b/LEGO1/omni/include/mxomni.h
index 55fb4e21..ebc7b5d3 100644
--- a/LEGO1/omni/include/mxomni.h
+++ b/LEGO1/omni/include/mxomni.h
@@ -6,6 +6,7 @@
 #include "mxcriticalsection.h"
 #include "mxstring.h"
 
+#include <SDL3/SDL_video.h>
 #include <windows.h>
 
 class MxAtomSet;
@@ -61,7 +62,9 @@ class MxOmni : public MxCore {
 	static void SetInstance(MxOmni* p_instance);
 	static MxBool ActionSourceEquals(MxDSAction* p_action, const char* p_name);
 
-	HWND GetWindowHandle() const { return this->m_windowHandle; }
+	SDL_Window* GetWindowHandle() const {
+        return m_windowHandle;
+    }
 
 	// FUNCTION: BETA10 0x10125100
 	MxObjectFactory* GetObjectFactory() const { return this->m_objectFactory; }
@@ -102,7 +105,7 @@ class MxOmni : public MxCore {
 	static MxOmni* g_instance;
 
 	MxString m_mediaPath;                         // 0x08
-	HWND m_windowHandle;                          // 0x18
+	SDL_Window* m_windowHandle;                   // 0x18
 	MxObjectFactory* m_objectFactory;             // 0x1c
 	MxVariableTable* m_variableTable;             // 0x20
 	MxTickleManager* m_tickleManager;             // 0x24
diff --git a/LEGO1/omni/include/mxomnicreateparam.h b/LEGO1/omni/include/mxomnicreateparam.h
index 65a19fd6..7e83e419 100644
--- a/LEGO1/omni/include/mxomnicreateparam.h
+++ b/LEGO1/omni/include/mxomnicreateparam.h
@@ -7,7 +7,7 @@
 #include "mxstring.h"
 #include "mxvideoparam.h"
 
-#include <windows.h>
+#include <SDL3/SDL_video.h>
 
 // VTABLE: LEGO1 0x100dc218
 // VTABLE: BETA10 0x101c1ca8
@@ -15,7 +15,7 @@ class MxOmniCreateParam : public MxParam {
 public:
 	LEGO1_EXPORT MxOmniCreateParam(
 		const char* p_mediaPath,
-		HWND p_windowHandle,
+		SDL_Window* p_windowHandle,
 		MxVideoParam& p_vparam,
 		MxOmniCreateFlags p_flags
 	);
@@ -24,7 +24,7 @@ class MxOmniCreateParam : public MxParam {
 	MxOmniCreateFlags& CreateFlags() { return this->m_createFlags; }
 
 	const MxString& GetMediaPath() const { return m_mediaPath; }
-	const HWND GetWindowHandle() const { return m_windowHandle; }
+	SDL_Window* GetWindowHandle() const { return m_windowHandle; }
 	MxVideoParam& GetVideoParam() { return m_videoParam; }
 	const MxVideoParam& GetVideoParam() const { return m_videoParam; }
 
@@ -34,7 +34,7 @@ class MxOmniCreateParam : public MxParam {
 
 private:
 	MxString m_mediaPath;            // 0x04
-	HWND m_windowHandle;             // 0x14
+	SDL_Window* m_windowHandle;      // 0x14
 	MxVideoParam m_videoParam;       // 0x18
 	MxOmniCreateFlags m_createFlags; // 0x3c
 };
diff --git a/LEGO1/omni/src/main/mxomnicreateparam.cpp b/LEGO1/omni/src/main/mxomnicreateparam.cpp
index 88235330..37133217 100644
--- a/LEGO1/omni/src/main/mxomnicreateparam.cpp
+++ b/LEGO1/omni/src/main/mxomnicreateparam.cpp
@@ -8,7 +8,7 @@ DECOMP_SIZE_ASSERT(MxOmniCreateParam, 0x40)
 // FUNCTION: BETA10 0x10130b6b
 MxOmniCreateParam::MxOmniCreateParam(
 	const char* p_mediaPath,
-	HWND p_windowHandle,
+	SDL_Window* p_windowHandle,
 	MxVideoParam& p_vparam,
 	MxOmniCreateFlags p_flags
 )
diff --git a/LEGO1/omni/src/video/mxdisplaysurface.cpp b/LEGO1/omni/src/video/mxdisplaysurface.cpp
index 6a2baddf..cb9c09b6 100644
--- a/LEGO1/omni/src/video/mxdisplaysurface.cpp
+++ b/LEGO1/omni/src/video/mxdisplaysurface.cpp
@@ -139,7 +139,13 @@ MxResult MxDisplaySurface::Create(MxVideoParam& p_videoParam)
 	DDSURFACEDESC ddsd;
 	MxResult result = FAILURE;
 	LPDIRECTDRAW lpDirectDraw = MVideoManager()->GetDirectDraw();
-	HWND hWnd = MxOmni::GetInstance()->GetWindowHandle();
+	SDL_Window* window = MxOmni::GetInstance()->GetWindowHandle();
+    HWND hWnd = (HWND
+       ) SDL_GetPointerProperty(SDL_GetWindowProperties(window), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+
+    if (!hWnd) {
+        goto done;
+    }
 
 	m_initialized = TRUE;
 	m_videoParam = p_videoParam;
@@ -842,7 +848,8 @@ void MxDisplaySurface::Display(MxS32 p_left, MxS32 p_top, MxS32 p_left2, MxS32 p
 		}
 		else {
 			MxPoint32 point(0, 0);
-			ClientToScreen(MxOmni::GetInstance()->GetWindowHandle(), (LPPOINT) &point);
+            HWND hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+			ClientToScreen(hWnd, (LPPOINT) &point);
 
 			p_left2 += m_videoParam.GetRect().GetLeft() + point.GetX();
 			p_top2 += m_videoParam.GetRect().GetTop() + point.GetY();
diff --git a/LEGO1/omni/src/video/mxvideomanager.cpp b/LEGO1/omni/src/video/mxvideomanager.cpp
index 9c99f944..3a17821e 100644
--- a/LEGO1/omni/src/video/mxvideomanager.cpp
+++ b/LEGO1/omni/src/video/mxvideomanager.cpp
@@ -216,6 +216,7 @@ MxResult MxVideoManager::Create(MxVideoParam& p_videoParam, MxU32 p_frequencyMS,
 {
 	MxBool locked = FALSE;
 	MxResult status = FAILURE;
+    HWND hWnd = NULL;
 
 	m_unk0x60 = TRUE;
 
@@ -237,7 +238,8 @@ MxResult MxVideoManager::Create(MxVideoParam& p_videoParam, MxU32 p_frequencyMS,
 		goto done;
 	}
 
-	if (m_pDirectDraw->SetCooperativeLevel(MxOmni::GetInstance()->GetWindowHandle(), DDSCL_NORMAL) != DD_OK) {
+    hWnd = (HWND) SDL_GetPointerProperty(SDL_GetWindowProperties(MxOmni::GetInstance()->GetWindowHandle()), SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+	if (m_pDirectDraw->SetCooperativeLevel(hWnd, DDSCL_NORMAL) != DD_OK) {
 		goto done;
 	}
 
diff --git a/util/compat.h b/util/compat.h
index ea2a6507..db768dda 100644
--- a/util/compat.h
+++ b/util/compat.h
@@ -3,7 +3,7 @@
 
 // Various macros to enable compiling with other/newer compilers.
 
-#if defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER >= 1100)
+#if defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER >= 1100) || !defined(_WIN32)
 #define COMPAT_MODE
 #endif