diff --git a/src/p_3dmidtex.cpp b/src/p_3dmidtex.cpp
index 4bb9ec4ba6..d04decfa03 100644
--- a/src/p_3dmidtex.cpp
+++ b/src/p_3dmidtex.cpp
@@ -236,7 +236,7 @@ bool P_GetMidTexturePosition(const line_t *line, int sideno, double *ptextop, do
 	double textureheight = tex->GetHeight() / totalscale;
 	if (totalscale != 1. && !tex->bWorldPanning)
 	{ 
-		y_offset *= totalscale;
+		y_offset /= totalscale;
 	}
 
 	if(line->flags & ML_DONTPEGBOTTOM)
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 00b3229b22..c880d87bf6 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -8637,8 +8637,11 @@ scriptwait:
 					else
 					{
 						item = activator->GiveInventoryType (static_cast<PClassAmmo *>(type));
-						item->MaxAmount = STACK(1);
-						item->Amount = 0;
+						if (item != NULL)
+						{
+							item->MaxAmount = STACK(1);
+							item->Amount = 0;
+						}
 					}
 				}
 			}
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 5d01f7af2e..76d083537c 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -5002,7 +5002,7 @@ bool P_UsePuzzleItem(AActor *PuzzleItemUser, int PuzzleItemType)
 	start = PuzzleItemUser->GetPortalTransition(PuzzleItemUser->Height / 2);
 	end = PuzzleItemUser->Angles.Yaw.ToVector(usedist);
 
-	FPathTraverse it(start.X, start.Y, end.X, end.Y, PT_ADDLINES | PT_ADDTHINGS);
+	FPathTraverse it(start.X, start.Y, end.X, end.Y, PT_DELTA | PT_ADDLINES | PT_ADDTHINGS);
 	intercept_t *in;
 
 	while ((in = it.Next()))
diff --git a/src/s_sound.cpp b/src/s_sound.cpp
index d1fee071e5..ac4dbc78fd 100644
--- a/src/s_sound.cpp
+++ b/src/s_sound.cpp
@@ -773,7 +773,7 @@ static void CalcSectorSoundOrg(const DVector3 &listenpos, const sector_t *sec, i
 	if (!(i_compatflags & COMPATF_SECTORSOUNDS))
 	{
 		// Are we inside the sector? If yes, the closest point is the one we're on.
-		if (P_PointInSector(pos.X, pos.Y) == sec)
+		if (P_PointInSector(listenpos.X, listenpos.Y) == sec)
 		{
 			pos.X = (float)listenpos.X;
 			pos.Z = (float)listenpos.Y;
diff --git a/src/textures/multipatchtexture.cpp b/src/textures/multipatchtexture.cpp
index 89fe947578..b0db481a89 100644
--- a/src/textures/multipatchtexture.cpp
+++ b/src/textures/multipatchtexture.cpp
@@ -1165,7 +1165,7 @@ void FMultiPatchTexture::ParsePatch(FScanner &sc, TexPart & part, bool silent, i
 			else if (sc.Compare("alpha"))
 			{
 				sc.MustGetFloat();
-				part.Alpha = clamp<blend_t>(int(sc.Float / BLENDUNIT), 0, BLENDUNIT);
+				part.Alpha = clamp<blend_t>(int(sc.Float * BLENDUNIT), 0, BLENDUNIT);
 				// bComplex is not set because it is only needed when the style is not OP_COPY.
 			}
 			else if (sc.Compare("style"))
diff --git a/src/win32/i_crash.cpp b/src/win32/i_crash.cpp
index 802a4d9e8e..4603fb4f98 100644
--- a/src/win32/i_crash.cpp
+++ b/src/win32/i_crash.cpp
@@ -542,7 +542,7 @@ static DWORD WINAPI WriteMiniDumpInAnotherThread (LPVOID lpParam)
 //
 //==========================================================================
 
-void __cdecl Writef (HANDLE file, const char *format, ...)
+void Writef (HANDLE file, const char *format, ...)
 {
 	char buffer[1024];
 	va_list args;
diff --git a/tools/zipdir/zipdir.c b/tools/zipdir/zipdir.c
index e21b9ba13b..cee41b12ed 100644
--- a/tools/zipdir/zipdir.c
+++ b/tools/zipdir/zipdir.c
@@ -56,10 +56,6 @@
 
 // MACROS ------------------------------------------------------------------
 
-#ifndef _WIN32
-#define __cdecl
-#endif
-
 #ifdef __GNUC__
 // With versions of GCC newer than 4.2, it appears it was determined that the
 // cost of an unaligned pointer on PPC was high enough to add padding to the
@@ -212,7 +208,7 @@ dir_tree_t *add_dir(const char *dirpath);
 #endif
 dir_tree_t *add_dirs(char **argv);
 int count_files(dir_tree_t *trees);
-int __cdecl sort_cmp(const void *a, const void *b);
+int sort_cmp(const void *a, const void *b);
 file_sorted_t *sort_files(dir_tree_t *trees, int num_files);
 void write_zip(const char *zipname, dir_tree_t *trees, int update);
 int append_to_zip(FILE *zip_file, file_sorted_t *file, FILE *ozip, BYTE *odir);
@@ -694,7 +690,7 @@ int count_files(dir_tree_t *trees)
 //
 //==========================================================================
 
-int __cdecl sort_cmp(const void *a, const void *b)
+int sort_cmp(const void *a, const void *b)
 {
 	const file_sorted_t *sort1 = (const file_sorted_t *)a;
 	const file_sorted_t *sort2 = (const file_sorted_t *)b;
@@ -1569,7 +1565,7 @@ int copy_zip_file(FILE *zip, file_entry_t *file, FILE *ozip, CentralDirectoryEnt
 //
 //==========================================================================
 
-int __cdecl main (int argc, char **argv)
+int main (int argc, char **argv)
 {
 	dir_tree_t *tree, *trees;
 	file_entry_t *file;