diff --git a/ISLE/isleapp.cpp b/ISLE/isleapp.cpp
index a16b6251..a42e4c14 100644
--- a/ISLE/isleapp.cpp
+++ b/ISLE/isleapp.cpp
@@ -89,7 +89,7 @@ IsleApp::IsleApp()
 	m_backBuffersInVram = TRUE;
 	m_using8bit = FALSE;
 	m_using16bit = TRUE;
-	m_unk0x24 = 0;
+	m_hasLightSupport = FALSE;
 	m_drawCursor = FALSE;
 	m_use3dSound = TRUE;
 	m_useMusic = TRUE;
@@ -214,7 +214,7 @@ void IsleApp::SetupVideoFlags(
 	MxS32 backBuffers,
 	MxS32 using8bit,
 	MxS32 using16bit,
-	MxS32 param_6,
+	MxS32 hasLightSupport,
 	MxS32 param_7,
 	MxS32 wideViewAngle,
 	char* deviceId
@@ -223,7 +223,7 @@ void IsleApp::SetupVideoFlags(
 	m_videoParam.Flags().SetFullScreen(fullScreen);
 	m_videoParam.Flags().SetFlipSurfaces(flipSurfaces);
 	m_videoParam.Flags().SetBackBuffers(!backBuffers);
-	m_videoParam.Flags().SetLacksLightSupport(!param_6);
+	m_videoParam.Flags().SetLacksLightSupport(!hasLightSupport);
 	m_videoParam.Flags().SetF1bit7(param_7);
 	m_videoParam.Flags().SetWideViewAngle(wideViewAngle);
 	m_videoParam.Flags().SetF2bit1(1);
@@ -479,7 +479,7 @@ MxResult IsleApp::SetupWindow()
 		m_backBuffersInVram,
 		m_using8bit,
 		m_using16bit,
-		m_unk0x24,
+		m_hasLightSupport,
 		FALSE,
 		m_wideViewAngle,
 		m_deviceId
diff --git a/ISLE/isleapp.h b/ISLE/isleapp.h
index 7fd3c84f..91248d35 100644
--- a/ISLE/isleapp.h
+++ b/ISLE/isleapp.h
@@ -64,7 +64,7 @@ class IsleApp {
 	MxS32 m_backBuffersInVram;   // 0x18
 	MxS32 m_using8bit;           // 0x1c
 	MxS32 m_using16bit;          // 0x20
-	MxS32 m_unk0x24;             // 0x24
+	MxS32 m_hasLightSupport;     // 0x24
 	MxS32 m_use3dSound;          // 0x28
 	MxS32 m_useMusic;            // 0x2c
 	MxS32 m_useJoystick;         // 0x30
diff --git a/LEGO1/lego/legoomni/src/video/legovideomanager.cpp b/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
index a1ca65b3..54f1d601 100644
--- a/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
+++ b/LEGO1/lego/legoomni/src/video/legovideomanager.cpp
@@ -137,7 +137,7 @@ MxResult LegoVideoManager::Create(MxVideoParam& p_videoParam, MxU32 p_frequencyM
 		p_videoParam.Flags().SetLacksLightSupport(FALSE);
 	}
 
-	ViewROI::SetUnk101013d8(p_videoParam.Flags().GetLacksLightSupport() == FALSE);
+	ViewROI::SetLightSupport(p_videoParam.Flags().GetLacksLightSupport() == FALSE);
 
 	if (!m_direct3d->Create(
 			hwnd,
diff --git a/LEGO1/library_msvc.h b/LEGO1/library_msvc.h
index 60f5988c..b0542e13 100644
--- a/LEGO1/library_msvc.h
+++ b/LEGO1/library_msvc.h
@@ -1,4 +1,4 @@
-#ifdef 0
+#if 0
 // For LEGO1 symbols only
 
 // aka `operator new`
diff --git a/LEGO1/library_smack.h b/LEGO1/library_smack.h
index 0967aeab..56d00db6 100644
--- a/LEGO1/library_smack.h
+++ b/LEGO1/library_smack.h
@@ -1,4 +1,4 @@
-#ifdef 0
+#if 0
 
 // LIBRARY: LEGO1 0x100cd782
 // LIBRARY: BETA10 0x1015fb82
diff --git a/LEGO1/omni/src/video/mxpalette.cpp b/LEGO1/omni/src/video/mxpalette.cpp
index 4c871971..14a09ed8 100644
--- a/LEGO1/omni/src/video/mxpalette.cpp
+++ b/LEGO1/omni/src/video/mxpalette.cpp
@@ -238,14 +238,14 @@ MxResult MxPalette::SetEntries(LPPALETTEENTRY p_entries)
 // FUNCTION: BETA10 0x101442aa
 MxResult MxPalette::SetSkyColor(LPPALETTEENTRY p_skyColor)
 {
-	MxResult status = 0;
+	MxResult status = SUCCESS;
 	if (m_palette != NULL) {
 		m_entries[141].peRed = p_skyColor->peRed;
 		m_entries[141].peGreen = p_skyColor->peGreen;
 		m_entries[141].peBlue = p_skyColor->peBlue;
 		m_skyColor = m_entries[141];
 		if (m_palette->SetEntries(0, 141, 1, &m_skyColor)) {
-			status = -1;
+			status = FAILURE;
 		}
 	}
 	return status;
diff --git a/LEGO1/tgl/d3drm/impl.h b/LEGO1/tgl/d3drm/impl.h
index d2728023..6b89568b 100644
--- a/LEGO1/tgl/d3drm/impl.h
+++ b/LEGO1/tgl/d3drm/impl.h
@@ -1,3 +1,5 @@
+#ifndef TGL_D3DRM_IMPL_H
+#define TGL_D3DRM_IMPL_H
 
 #include "compat.h"
 #include "decomp.h"
@@ -820,3 +822,5 @@ inline D3DRMLIGHTTYPE Translate(LightType tglLightType)
 // IID_IDirect3DRMMeshBuilder
 
 } /* namespace TglImpl */
+
+#endif
diff --git a/LEGO1/viewmanager/viewroi.cpp b/LEGO1/viewmanager/viewroi.cpp
index 8d8cbb6b..626fe311 100644
--- a/LEGO1/viewmanager/viewroi.cpp
+++ b/LEGO1/viewmanager/viewroi.cpp
@@ -7,7 +7,7 @@
 DECOMP_SIZE_ASSERT(ViewROI, 0xe4)
 
 // GLOBAL: LEGO1 0x101013d8
-undefined g_unk101013d8 = 0;
+unsigned char g_lightSupport = FALSE;
 
 // FUNCTION: LEGO1 0x100a9eb0
 float ViewROI::IntrinsicImportance() const
@@ -78,9 +78,9 @@ void ViewROI::VTable0x1c()
 }
 
 // FUNCTION: LEGO1 0x100aa500
-undefined ViewROI::SetUnk101013d8(undefined p_flag)
+unsigned char ViewROI::SetLightSupport(unsigned char p_lightSupport)
 {
-	undefined oldFlag = g_unk101013d8;
-	g_unk101013d8 = p_flag;
+	unsigned char oldFlag = g_lightSupport;
+	g_lightSupport = p_lightSupport;
 	return oldFlag;
 }
diff --git a/LEGO1/viewmanager/viewroi.h b/LEGO1/viewmanager/viewroi.h
index 444e18f0..a6d2da11 100644
--- a/LEGO1/viewmanager/viewroi.h
+++ b/LEGO1/viewmanager/viewroi.h
@@ -59,7 +59,7 @@ class ViewROI : public OrientableROI {
 	int GetUnknown0xe0() { return m_unk0xe0; }
 	void SetUnknown0xe0(int p_unk0xe0) { m_unk0xe0 = p_unk0xe0; }
 
-	static undefined SetUnk101013d8(undefined p_flag);
+	static unsigned char SetLightSupport(unsigned char p_lightSupport);
 
 protected:
 	void UpdateWorldData(const Matrix4& parent2world) override; // vtable+0x28