diff --git a/source/common/engine/palettecontainer.cpp b/source/common/engine/palettecontainer.cpp
index 2e85bd688..ae4f4a829 100644
--- a/source/common/engine/palettecontainer.cpp
+++ b/source/common/engine/palettecontainer.cpp
@@ -32,6 +32,7 @@
 **
 */
 
+#include <cmath>
 #include "palutil.h"
 #include "sc_man.h"
 #include "m_crc32.h"
diff --git a/source/common/engine/serializer.cpp b/source/common/engine/serializer.cpp
index 4e4364c96..261aa464c 100644
--- a/source/common/engine/serializer.cpp
+++ b/source/common/engine/serializer.cpp
@@ -55,6 +55,7 @@
 #include "textures.h"
 #include "texturemanager.h"
 #include "base64.h"
+#include "vm.h"
 #include "i_interface.h"
 
 using namespace FileSys;
@@ -1591,6 +1592,35 @@ template<> FSerializer &Serialize(FSerializer &arc, const char *key, Dictionary
 	}
 }
 
+template<> FSerializer& Serialize(FSerializer& arc, const char* key, VMFunction*& func, VMFunction**)
+{
+	if (arc.isWriting())
+	{
+		arc.WriteKey(key);
+		if (func) arc.w->String(func->QualifiedName);
+		else arc.w->Null();
+	}
+	else
+	{
+		func = nullptr;
+
+		auto val = arc.r->FindKey(key);
+		if (val != nullptr && val->IsString())
+		{
+			auto qname = val->GetString();
+			size_t p = strcspn(qname, ".");
+			if (p != 0)
+			{
+				FName clsname(qname, p, true);
+				FName funcname(qname + p + 1, true);
+				func = PClass::FindFunction(clsname, funcname);
+			}
+		}
+
+	}
+	return arc;
+}
+
 //==========================================================================
 //
 // Handler to retrieve a numeric value of any kind.
diff --git a/source/common/engine/serializer.h b/source/common/engine/serializer.h
index 047d43f54..29677237b 100644
--- a/source/common/engine/serializer.h
+++ b/source/common/engine/serializer.h
@@ -324,6 +324,7 @@ inline FSerializer& Serialize(FSerializer& arc, const char* key, BitArray& value
 template<> FSerializer& Serialize(FSerializer& arc, const char* key, PClass*& clst, PClass** def);
 template<> FSerializer& Serialize(FSerializer& arc, const char* key, FFont*& font, FFont** def);
 template<> FSerializer &Serialize(FSerializer &arc, const char *key, Dictionary *&dict, Dictionary **def);
+template<> FSerializer& Serialize(FSerializer& arc, const char* key, VMFunction*& dict, VMFunction** def);
 
 inline FSerializer &Serialize(FSerializer &arc, const char *key, DVector3 &p, DVector3 *def)
 {
diff --git a/source/common/objects/autosegs.cpp b/source/common/objects/autosegs.cpp
index 11fce1005..e9b3f935f 100644
--- a/source/common/objects/autosegs.cpp
+++ b/source/common/objects/autosegs.cpp
@@ -42,6 +42,7 @@
 ** compile with something other than Visual C++ or GCC.
 */
 
+#include <cassert>
 #include "autosegs.h"
 
 #ifdef _WIN32
diff --git a/source/common/objects/autosegs.h b/source/common/objects/autosegs.h
index 838553dd4..e015ea9f5 100644
--- a/source/common/objects/autosegs.h
+++ b/source/common/objects/autosegs.h
@@ -36,6 +36,7 @@
 #define AUTOSEGS_H
 
 #include <type_traits>
+#include <cstdint>
 
 #if defined(__clang__)
 #if defined(__has_feature) && __has_feature(address_sanitizer)
diff --git a/source/common/platform/posix/sdl/i_joystick.cpp b/source/common/platform/posix/sdl/i_joystick.cpp
index 3ff0cc169..a7eb59568 100644
--- a/source/common/platform/posix/sdl/i_joystick.cpp
+++ b/source/common/platform/posix/sdl/i_joystick.cpp
@@ -268,7 +268,9 @@ protected:
 
 	friend class SDLInputJoystickManager;
 };
-const EJoyAxis SDLInputJoystick::DefaultAxes[5] = {JOYAXIS_Side, JOYAXIS_Forward, JOYAXIS_Pitch, JOYAXIS_Yaw, JOYAXIS_Up};
+
+// [Nash 4 Feb 2024] seems like on Linux, the third axis is actually the Left Trigger, resulting in the player uncontrollably looking upwards.
+const EJoyAxis SDLInputJoystick::DefaultAxes[5] = {JOYAXIS_Side, JOYAXIS_Forward, JOYAXIS_None, JOYAXIS_Yaw, JOYAXIS_Pitch};
 
 class SDLInputJoystickManager
 {
diff --git a/source/common/rendering/hwrenderer/data/hw_vrmodes.cpp b/source/common/rendering/hwrenderer/data/hw_vrmodes.cpp
index 4534829ab..c51ce2ee9 100644
--- a/source/common/rendering/hwrenderer/data/hw_vrmodes.cpp
+++ b/source/common/rendering/hwrenderer/data/hw_vrmodes.cpp
@@ -146,27 +146,11 @@ float VREyeInfo::getShift() const
 	return vr_swap_eyes ? -res : res;
 }
 
-VSMatrix VREyeInfo::GetProjection(float fov, float aspectRatio, float fovRatio, bool iso_ortho) const
+VSMatrix VREyeInfo::GetProjection(float fov, float aspectRatio, float fovRatio) const
 {
 	VSMatrix result;
 
-	if (iso_ortho) // Orthographic projection for isometric viewpoint
-	{
-		double zNear = -1.0; // screen->GetZNear();
-		double zFar = screen->GetZFar();
-
-		double fH = tan(DEG2RAD(fov) / 2) / fovRatio;
-		double fW = fH * aspectRatio * mScaleFactor;
-		double left = -fW;
-		double right = fW;
-		double bottom = -fH;
-		double top = fH;
-
-		VSMatrix fmat(1);
-		fmat.ortho((float)left, (float)right, (float)bottom, (float)top, (float)zNear, (float)zFar);
-		return fmat;
-	}
-	else if (mShiftFactor == 0)
+	if (mShiftFactor == 0)
 	{
 		float fovy = (float)(2 * RAD2DEG(atan(tan(DEG2RAD(fov) / 2) / fovRatio)));
 		result.perspective(fovy, aspectRatio, screen->GetZNear(), screen->GetZFar());
diff --git a/source/common/rendering/hwrenderer/data/hw_vrmodes.h b/source/common/rendering/hwrenderer/data/hw_vrmodes.h
index 989281520..26c9fd211 100644
--- a/source/common/rendering/hwrenderer/data/hw_vrmodes.h
+++ b/source/common/rendering/hwrenderer/data/hw_vrmodes.h
@@ -27,7 +27,7 @@ struct VREyeInfo
 	float mShiftFactor;
 	float mScaleFactor;
 
-	VSMatrix GetProjection(float fov, float aspectRatio, float fovRatio, bool iso_ortho) const;
+	VSMatrix GetProjection(float fov, float aspectRatio, float fovRatio) const;
 	DVector3 GetViewShift(float yaw) const;
 private:
 	float getShift() const;
diff --git a/source/common/textures/bitmap.h b/source/common/textures/bitmap.h
index 2828be356..418f256c2 100644
--- a/source/common/textures/bitmap.h
+++ b/source/common/textures/bitmap.h
@@ -36,6 +36,7 @@
 #ifndef __BITMAP_H__
 #define __BITMAP_H__
 
+#include <cstring>
 #include "palentry.h"
 
 struct FCopyInfo;
diff --git a/source/common/thirdparty/md5.h b/source/common/thirdparty/md5.h
index f3aab94d9..95ac9a50d 100644
--- a/source/common/thirdparty/md5.h
+++ b/source/common/thirdparty/md5.h
@@ -18,6 +18,8 @@
 #ifndef MD5_H
 #define MD5_H
 
+#include <cstdint>
+
 struct MD5Context
 {
 	MD5Context() { Init(); }
diff --git a/source/common/utility/engineerrors.cpp b/source/common/utility/engineerrors.cpp
index 41485778a..05897b786 100644
--- a/source/common/utility/engineerrors.cpp
+++ b/source/common/utility/engineerrors.cpp
@@ -35,8 +35,9 @@
 
 bool gameisdead;
 
-#ifdef _WIN32
 #include <cstdarg>
+
+#ifdef _WIN32
 #include <windows.h>
 #include "zstring.h"
 void I_DebugPrint(const char *cp)
diff --git a/source/common/utility/palette.cpp b/source/common/utility/palette.cpp
index ea046a220..03517c1ba 100644
--- a/source/common/utility/palette.cpp
+++ b/source/common/utility/palette.cpp
@@ -33,6 +33,8 @@
 */
 
 #include <algorithm>
+#include <cfloat>
+#include <cmath>
 #include "palutil.h"
 #include "palentry.h"
 #include "sc_man.h"
diff --git a/source/common/utility/writezip.cpp b/source/common/utility/writezip.cpp
index a6f6f9a27..2f3507e6f 100644
--- a/source/common/utility/writezip.cpp
+++ b/source/common/utility/writezip.cpp
@@ -39,6 +39,7 @@
 #include "files.h"
 #include "m_swap.h"
 #include "w_zip.h"
+#include "fs_decompress.h"
 
 using FileSys::FCompressedBuffer;
 
diff --git a/source/common/widgets/netstartwindow.cpp b/source/common/widgets/netstartwindow.cpp
index c45f30098..69c83e565 100644
--- a/source/common/widgets/netstartwindow.cpp
+++ b/source/common/widgets/netstartwindow.cpp
@@ -2,6 +2,7 @@
 #include "netstartwindow.h"
 #include "version.h"
 #include "engineerrors.h"
+#include "gstrings.h"
 #include <zwidget/core/timer.h>
 #include <zwidget/widgets/textlabel/textlabel.h>
 #include <zwidget/widgets/pushbutton/pushbutton.h>