diff --git a/src/compatibility.cpp b/src/compatibility.cpp
index b93cb68f23..e091a7f1eb 100644
--- a/src/compatibility.cpp
+++ b/src/compatibility.cpp
@@ -185,7 +185,7 @@ void ParseCompatibility()
 		} while (!sc.Compare("{"));
 		flags.CompatFlags = 0;
 		flags.BCompatFlags = 0;
-		flags.ExtCommandIndex = -1;
+		flags.ExtCommandIndex = ~0u;
 		while (sc.GetString())
 		{
 			if ((i = sc.MatchString(&Options[0].Name, sizeof(*Options))) >= 0)
@@ -195,7 +195,7 @@ void ParseCompatibility()
 			}
 			else if (sc.Compare("clearlineflags"))
 			{
-				if (flags.ExtCommandIndex == -1) flags.ExtCommandIndex = CompatParams.Size();
+				if (flags.ExtCommandIndex == ~0u) flags.ExtCommandIndex = CompatParams.Size();
 				CompatParams.Push(CP_CLEARFLAGS);
 				sc.MustGetNumber();
 				CompatParams.Push(sc.Number);
@@ -204,7 +204,7 @@ void ParseCompatibility()
 			}
 			else if (sc.Compare("setlineflags"))
 			{
-				if (flags.ExtCommandIndex == -1) flags.ExtCommandIndex = CompatParams.Size();
+				if (flags.ExtCommandIndex == ~0u) flags.ExtCommandIndex = CompatParams.Size();
 				CompatParams.Push(CP_SETFLAGS);
 				sc.MustGetNumber();
 				CompatParams.Push(sc.Number);
@@ -213,7 +213,7 @@ void ParseCompatibility()
 			}
 			else if (sc.Compare("setlinespecial"))
 			{
-				if (flags.ExtCommandIndex == -1) flags.ExtCommandIndex = CompatParams.Size();
+				if (flags.ExtCommandIndex == ~0u) flags.ExtCommandIndex = CompatParams.Size();
 				CompatParams.Push(CP_SETSPECIAL);
 				sc.MustGetNumber();
 				CompatParams.Push(sc.Number);
@@ -232,7 +232,7 @@ void ParseCompatibility()
 				break;
 			}
 		}
-		if (flags.ExtCommandIndex != -1) 
+		if (flags.ExtCommandIndex != ~0u) 
 		{
 			CompatParams.Push(CP_END);
 		}
diff --git a/src/dobject.cpp b/src/dobject.cpp
index 073be864f8..3bd815bd60 100644
--- a/src/dobject.cpp
+++ b/src/dobject.cpp
@@ -190,7 +190,7 @@ const char *FMetaTable::GetMetaString (DWORD id) const
 
 CCMD (dumpactors)
 {
-	char * filters[32] =
+	const char *const filters[32] =
 	{
 		"0:All", "1:Doom", "2:Heretic", "3:DoomHeretic", "4:Hexen", "5:DoomHexen", "6:Raven", "7:IdRaven",
 		"8:Strife", "9:DoomStrife", "10:HereticStrife", "11:DoomHereticStrife", "12:HexenStrife", 
diff --git a/src/m_misc.cpp b/src/m_misc.cpp
index 1f8b9f3e6c..324095d5c8 100644
--- a/src/m_misc.cpp
+++ b/src/m_misc.cpp
@@ -167,7 +167,7 @@ void M_FindResponseFile (void)
 			int		argc = 0;
 			FILE	*handle;
 			int 	size;
-			long	argsize;
+			long	argsize = 0;
 			int 	index;
 
 			// Any more response files after the limit will be removed from the
diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index e982ea0d0e..cbbd8797f7 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -2688,7 +2688,7 @@ void A_FaceTarget (AActor *self, angle_t max_turn)
 
 	// 0 means no limit. Also, if we turn in a single step anyways, no need to go through the algorithms.
 	// It also means that there is no need to check for going past the target.
-	if (max_turn && (max_turn < abs(self->angle - target_angle)))
+	if (max_turn && (max_turn < (angle_t)abs(self->angle - target_angle)))
 	{
 		if (self->angle > target_angle)
 		{
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 16c70ef186..39a56eced5 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -1566,7 +1566,7 @@ bool P_SeekerMissile (AActor *actor, angle_t thresh, angle_t turnMax, bool preci
 	}
 	else
 	{
-		angle_t pitch;
+		angle_t pitch = 0;
 		if (!(actor->flags3 & (MF3_FLOORHUGGER|MF3_CEILINGHUGGER)))
 		{ // Need to seek vertically
 			double dist = MAX(1.0, FVector2(target->x - actor->x, target->y - actor->y).Length());
diff --git a/src/r_segs.cpp b/src/r_segs.cpp
index 5bb3a09fcf..eed5d78a83 100644
--- a/src/r_segs.cpp
+++ b/src/r_segs.cpp
@@ -1781,6 +1781,7 @@ int OWallMost (short *mostbuf, fixed_t z)
 	s3 = MulScale16 (globaldclip, WallSZ1); s4 = MulScale16 (globaldclip, WallSZ2);
 	bad = (z<s1)+((z<s2)<<1)+((z>s3)<<2)+((z>s4)<<3);
 
+#if 1
 	if ((bad&3) == 3)
 	{
 		memset (&mostbuf[WallSX1], 0, (WallSX2 - WallSX1)*sizeof(mostbuf[0]));
@@ -1792,10 +1793,10 @@ int OWallMost (short *mostbuf, fixed_t z)
 		clearbufshort (&mostbuf[WallSX1], WallSX2 - WallSX1, viewheight);
 		return bad;
 	}
-
+#endif
 	ix1 = WallSX1; iy1 = WallSZ1;
 	ix2 = WallSX2; iy2 = WallSZ2;
-
+#if 1
 	if (bad & 3)
 	{
 		int t = DivScale30 (z-s1, s2-s1);
@@ -1842,7 +1843,38 @@ int OWallMost (short *mostbuf, fixed_t z)
 		fixed_t yinc  = (Scale (z, InvZtoScale, iy2) - y) / (ix2 - ix1);
 		qinterpolatedown16short (&mostbuf[ix1], ix2-ix1, y + centeryfrac, yinc);
 	}
+#else
+	double max = viewheight;
+	double zz = z / 65536.0;
+#if 0
+	double z1 = zz * InvZtoScale / WallSZ1;
+	double z2 = zz * InvZtoScale / WallSZ2 - z1;
+	z2 /= (WallSX2 - WallSX1);
+	z1 += centeryfrac / 65536.0;
 
+	for (int x = WallSX1; x < WallSX2; ++x)
+	{
+		mostbuf[x] = xs_RoundToInt(clamp(z1, 0.0, max));
+		z1 += z2;
+	}
+#else
+	double top, bot, i;
+
+	i = WallSX1 - centerx;
+	top = WallUoverZorg + WallUoverZstep * i;
+	bot = WallInvZorg + WallInvZstep * i;
+	double cy = centeryfrac / 65536.0;
+
+	for (int x = WallSX1; x < WallSX2; x++)
+	{
+		double frac = top / bot;
+		double scale = frac * WallDepthScale + WallDepthOrg;
+		mostbuf[x] = xs_RoundToInt(clamp(zz / scale + cy, 0.0, max));
+		top += WallUoverZstep;
+		bot += WallInvZstep;
+	}
+#endif
+#endif
 	if (mostbuf[ix1] < 0) mostbuf[ix1] = 0;
 	else if (mostbuf[ix1] > viewheight) mostbuf[ix1] = (short)viewheight;
 	if (mostbuf[ix2] < 0) mostbuf[ix2] = 0;
@@ -2046,13 +2078,10 @@ void PrepWall (fixed_t *swall, fixed_t *lwall, fixed_t walxrepeat)
 { // swall = scale, lwall = texturecolumn
 	double top, bot, i;
 	double xrepeat = walxrepeat;
-	double topinc, botinc;
 
 	i = WallSX1 - centerx;
 	top = WallUoverZorg + WallUoverZstep * i;
 	bot = WallInvZorg + WallInvZstep * i;
-	topinc = WallUoverZstep * 4.f;
-	botinc = WallInvZstep * 4.f;
 
 	for (int x = WallSX1; x < WallSX2; x++)
 	{
@@ -2069,14 +2098,11 @@ void PrepLWall (fixed_t *lwall, fixed_t walxrepeat)
 { // lwall = texturecolumn
 	double top, bot, i;
 	double xrepeat = walxrepeat;
-	double topinc, botinc;
 	double topstep;
 
 	i = WallSX1 - centerx;
 	top = WallUoverZorg + WallUoverZstep * i;
 	bot = WallInvZorg + WallInvZstep * i;
-	topinc = WallUoverZstep * 4.f;
-	botinc = WallInvZstep * 4.f;
 
 	top *= xrepeat;
 	topstep = WallUoverZstep * xrepeat;
diff --git a/src/sound/fmodsound.cpp b/src/sound/fmodsound.cpp
index a31665803d..30efe22d9c 100644
--- a/src/sound/fmodsound.cpp
+++ b/src/sound/fmodsound.cpp
@@ -1533,7 +1533,7 @@ static void SetCustomLoopPts(FMOD::Sound *sound)
 		FMOD_MODE mode;
 		if (FMOD_OK == (sound->getMode(&mode)))
 		{
-			sound->setMode(mode & ~(FMOD_LOOP_OFF | FMOD_LOOP_NORMAL) | FMOD_LOOP_BIDI);
+			sound->setMode((mode & ~(FMOD_LOOP_OFF | FMOD_LOOP_NORMAL)) | FMOD_LOOP_BIDI);
 		}
 	}
 }
diff --git a/src/sound/music_mus_midiout.cpp b/src/sound/music_mus_midiout.cpp
index 68558bdadb..b89d9fd67d 100644
--- a/src/sound/music_mus_midiout.cpp
+++ b/src/sound/music_mus_midiout.cpp
@@ -125,7 +125,7 @@ MUSSong2::MUSSong2 (FILE *file, BYTE *musiccache, int len, EMIDIDevice type)
 
 	// Read the remainder of the song.
 	len = int(len - start);
-	if (len < sizeof(MusHeader))
+	if (len < (int)sizeof(MusHeader))
 	{ // It's too short.
 		return;
 	}
diff --git a/src/win32/win32video.cpp b/src/win32/win32video.cpp
index a610fd4090..672e81df35 100644
--- a/src/win32/win32video.cpp
+++ b/src/win32/win32video.cpp
@@ -38,6 +38,7 @@
 #define DIRECTDRAW_VERSION 0x0300
 #define DIRECT3D_VERSION 0x0900
 
+#define _WIN32_WINNT 0x0501
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #include <ddraw.h>
@@ -51,6 +52,7 @@
 #include <ddraw.h>
 #include <d3d9.h>
 #include <stdio.h>
+#include <ctype.h>
 
 #define USE_WINDOWS_DWORD
 #include "doomtype.h"