diff --git a/src/common/2d/v_2ddrawer.h b/src/common/2d/v_2ddrawer.h
index 7203ca3c1..fc2970b15 100644
--- a/src/common/2d/v_2ddrawer.h
+++ b/src/common/2d/v_2ddrawer.h
@@ -217,7 +217,7 @@ public:
 		double originx, double originy, double scalex, double scaley,
 		DAngle rotation, const FColormap &colormap, PalEntry flatcolor, double lightlevel, uint32_t *indices, size_t indexcount);
 	void AddPoly(FGameTexture* img, FVector4 *vt, size_t vtcount, const unsigned int *ind, size_t idxcount, int translation, PalEntry color, FRenderStyle style, const IntRect* clip);
-	void FillPolygon(int* rx1, int* ry1, int* xb1, int32_t npoints, int picnum, int palette, int shade, int props, const FVector2& xtex, const FVector2& ytex, const FVector2& otex,
+	void FillPolygon(int* rx1, int* ry1, int* xb1, int32_t npoints, int pic, int palette, int shade, int props, const FVector2& xtex, const FVector2& ytex, const FVector2& otex,
 		int clipx1, int clipy1, int clipx2, int clipy2);
 	void AddFlatFill(int left, int top, int right, int bottom, FGameTexture *src, int local_origin = false, double flatscale = 1.0, PalEntry color = 0xffffffff, ERenderStyle rs = STYLE_Normal);
 
diff --git a/src/common/2d/v_draw.cpp b/src/common/2d/v_draw.cpp
index 7c1beb0c8..85ed31517 100644
--- a/src/common/2d/v_draw.cpp
+++ b/src/common/2d/v_draw.cpp
@@ -1786,12 +1786,12 @@ DEFINE_ACTION_FUNCTION(FCanvas, Dim)
 //
 //==========================================================================
 
-void DrawBorder (F2DDrawer *drawer, FTextureID picnum, int x1, int y1, int x2, int y2)
+void DrawBorder (F2DDrawer *drawer, FTextureID texid, int x1, int y1, int x2, int y2)
 {
 	int filltype = (ui_screenborder_classic_scaling) ? -1 : 0;
-	if (picnum.isValid())
+	if (texid.isValid())
 	{
-		drawer->AddFlatFill (x1, y1, x2, y2, TexMan.GetGameTexture(picnum, false), filltype);
+		drawer->AddFlatFill (x1, y1, x2, y2, TexMan.GetGameTexture(texid, false), filltype);
 	}
 	else
 	{
diff --git a/src/common/audio/sound/i_soundinternal.h b/src/common/audio/sound/i_soundinternal.h
index 1ef4178d4..4787aa12a 100644
--- a/src/common/audio/sound/i_soundinternal.h
+++ b/src/common/audio/sound/i_soundinternal.h
@@ -32,6 +32,7 @@ enum EChanFlag
 	CHANF_LOCAL = 16384,	// only plays locally for the calling actor
 	CHANF_TRANSIENT = 32768,	// Do not record in savegames - used for sounds that get restarted outside the sound system (e.g. ambients in SW and Blood)
 	CHANF_FORCE = 65536,		// Start, even if sound is paused.
+	CHANF_SINGULAR = 0x20000,		// Only start if no sound of this name is already playing.
 };
 
 typedef TFlags<EChanFlag> EChanFlags;
diff --git a/src/common/audio/sound/s_sound.cpp b/src/common/audio/sound/s_sound.cpp
index f3b0fb412..2544d1f87 100644
--- a/src/common/audio/sound/s_sound.cpp
+++ b/src/common/audio/sound/s_sound.cpp
@@ -488,7 +488,7 @@ FSoundChan *SoundEngine::StartSound(int type, const void *source,
 	}
 
 	// If this is a singular sound, don't play it if it's already playing.
-	if (sfx->bSingular && CheckSingular(sound_id))
+	if ((sfx->bSingular || (flags & CHANF_SINGULAR)) && CheckSingular(sound_id))
 	{
 		chanflags |= CHANF_EVICTED;
 	}
diff --git a/src/common/audio/sound/s_soundinternal.h b/src/common/audio/sound/s_soundinternal.h
index dae8a0ee2..782fbe325 100644
--- a/src/common/audio/sound/s_soundinternal.h
+++ b/src/common/audio/sound/s_soundinternal.h
@@ -90,6 +90,7 @@ constexpr FSoundID INVALID_SOUND = FSoundID::fromInt(-1);
 	 float		DefPitchMax = 0.f;					// Randomized range with stronger control over pitch itself.
 
 	 int16_t		NearLimit = 4;						// 0 means unlimited.
+	 int16_t		UserVal = 0;					// repurpose this gap for something useful
 	 uint8_t		PitchMask = 0;
 	 bool		bRandomHeader = false;
 	 bool		bLoadRAW = false;
@@ -99,17 +100,16 @@ constexpr FSoundID INVALID_SOUND = FSoundID::fromInt(-1);
 	 bool		bTentative = true;
 	 bool		bExternal = false;
 
-	 TArray<int> UserData;
-
 	 int			RawRate = 0;				// Sample rate to use when bLoadRAW is true
 	 int			LoopStart = -1;				// -1 means no specific loop defined
 	 int			LoopEnd = -1;				// -1 means no specific loop defined
+	 float		Attenuation = 1.f;			// Multiplies the attenuation passed to S_Sound.
 
 	 FSoundID link = NO_LINK;
 	 constexpr static FSoundID NO_LINK = FSoundID::fromInt(-1);
 
+	 TArray<int> UserData;
 	 FRolloffInfo	Rolloff{};
-	 float		Attenuation = 1.f;			// Multiplies the attenuation passed to S_Sound.
  };
 
 
diff --git a/src/common/cutscenes/playmve.cpp b/src/common/cutscenes/playmve.cpp
index 70b56b43a..3c49e9610 100644
--- a/src/common/cutscenes/playmve.cpp
+++ b/src/common/cutscenes/playmve.cpp
@@ -546,7 +546,7 @@ bool InterplayDecoder::Open(FileReader &fr_)
     int chunkType = LE_16(&chunkPreamble[2]);
     if (chunkType == CHUNK_VIDEO)
         bAudioEnabled = false;
-    else
+    else if (bAudioEnabled)
     {
         if (ProcessNextChunk() != CHUNK_INIT_AUDIO)
         {
diff --git a/src/common/engine/namedef.h b/src/common/engine/namedef.h
index 92fa6fa34..2571cb315 100644
--- a/src/common/engine/namedef.h
+++ b/src/common/engine/namedef.h
@@ -270,3 +270,4 @@ xx(BuiltinNameToClass)
 xx(BuiltinClassCast)
 
 xx(ScreenJobRunner)
+xx(Action)
diff --git a/src/common/engine/sc_man_scanner.re b/src/common/engine/sc_man_scanner.re
index 59c3c7712..b5cce6d09 100644
--- a/src/common/engine/sc_man_scanner.re
+++ b/src/common/engine/sc_man_scanner.re
@@ -220,6 +220,7 @@ std2:
 		'bright'					{ RET(StateOptions ? TK_Bright : TK_Identifier); }
 		'fast'						{ RET(StateOptions ? TK_Fast : TK_Identifier); }
 		'slow'						{ RET(StateOptions ? TK_Slow : TK_Identifier); }
+		'ticadjust'					{ RET(StateOptions ? TK_NoDelay : TK_Identifier); }	
 		'nodelay'					{ RET(StateOptions ? TK_NoDelay : TK_Identifier); }
 		'canraise'					{ RET(StateOptions ? TK_CanRaise : TK_Identifier); }
 		'offset'					{ RET(StateOptions ? TK_Offset : TK_Identifier); }
diff --git a/src/common/fonts/singlepicfont.cpp b/src/common/fonts/singlepicfont.cpp
index 687602876..30fdf8711 100644
--- a/src/common/fonts/singlepicfont.cpp
+++ b/src/common/fonts/singlepicfont.cpp
@@ -65,21 +65,21 @@ protected:
 FSinglePicFont::FSinglePicFont(const char *picname) :
 	FFont(-1) // Since lump is only needed for priority information we don't need to worry about this here.
 {
-	FTextureID picnum = TexMan.CheckForTexture (picname, ETextureType::Any);
+	FTextureID texid = TexMan.CheckForTexture (picname, ETextureType::Any);
 
-	if (!picnum.isValid())
+	if (!texid.isValid())
 	{
 		I_FatalError ("%s is not a font or texture", picname);
 	}
 
-	auto pic = TexMan.GetGameTexture(picnum);
+	auto pic = TexMan.GetGameTexture(texid);
 
 	FontName = picname;
 	FontHeight = (int)pic->GetDisplayHeight();
 	SpaceWidth = (int)pic->GetDisplayWidth();
 	GlobalKerning = 0;
 	FirstChar = LastChar = 'A';
-	PicNum = picnum;
+	PicNum = texid;
 }
 
 //==========================================================================
diff --git a/src/common/fonts/v_font.cpp b/src/common/fonts/v_font.cpp
index f51813aeb..cb206a4ec 100644
--- a/src/common/fonts/v_font.cpp
+++ b/src/common/fonts/v_font.cpp
@@ -138,10 +138,10 @@ FFont *V_GetFont(const char *name, const char *fontlumpname)
 				return font;
 			}
 		}
-		FTextureID picnum = TexMan.CheckForTexture (name, ETextureType::Any);
-		if (picnum.isValid())
+		FTextureID texid = TexMan.CheckForTexture (name, ETextureType::Any);
+		if (texid.isValid())
 		{
-			auto tex = TexMan.GetGameTexture(picnum);
+			auto tex = TexMan.GetGameTexture(texid);
 			if (tex && tex->GetSourceLump() >= folderfile)
 			{
 				FFont *CreateSinglePicFont(const char *name);
diff --git a/src/common/rendering/gl/gl_framebuffer.cpp b/src/common/rendering/gl/gl_framebuffer.cpp
index 6ea31e5bd..4b20db68f 100644
--- a/src/common/rendering/gl/gl_framebuffer.cpp
+++ b/src/common/rendering/gl/gl_framebuffer.cpp
@@ -63,7 +63,6 @@
 #include "hw_cvars.h"
 
 EXTERN_CVAR (Bool, vid_vsync)
-EXTERN_CVAR(Bool, r_drawvoxels)
 EXTERN_CVAR(Int, gl_tonemap)
 EXTERN_CVAR(Bool, cl_capfps)
 EXTERN_CVAR(Int, gl_pipeline_depth);
diff --git a/src/common/rendering/gles/gles_framebuffer.cpp b/src/common/rendering/gles/gles_framebuffer.cpp
index 0d0a459c0..bbade7896 100644
--- a/src/common/rendering/gles/gles_framebuffer.cpp
+++ b/src/common/rendering/gles/gles_framebuffer.cpp
@@ -61,7 +61,6 @@
 #include "hw_cvars.h"
 
 EXTERN_CVAR (Bool, vid_vsync)
-EXTERN_CVAR(Bool, r_drawvoxels)
 EXTERN_CVAR(Int, gl_tonemap)
 EXTERN_CVAR(Bool, cl_capfps)
 EXTERN_CVAR(Int, gl_pipeline_depth);
diff --git a/src/common/rendering/vulkan/system/vk_renderdevice.cpp b/src/common/rendering/vulkan/system/vk_renderdevice.cpp
index 8f4f1b737..7ef3e5531 100644
--- a/src/common/rendering/vulkan/system/vk_renderdevice.cpp
+++ b/src/common/rendering/vulkan/system/vk_renderdevice.cpp
@@ -68,7 +68,6 @@
 
 FString JitCaptureStackTrace(int framesToSkip, bool includeNativeFrames, int maxFrames = -1);
 
-EXTERN_CVAR(Bool, r_drawvoxels)
 EXTERN_CVAR(Int, gl_tonemap)
 EXTERN_CVAR(Int, screenblocks)
 EXTERN_CVAR(Bool, cl_capfps)
diff --git a/src/common/scripting/frontend/zcc-parse.lemon b/src/common/scripting/frontend/zcc-parse.lemon
index 1a9146f37..71385c582 100644
--- a/src/common/scripting/frontend/zcc-parse.lemon
+++ b/src/common/scripting/frontend/zcc-parse.lemon
@@ -272,6 +272,13 @@ dottable_id(X) ::= IDENTIFIER(A).
 	id->Id = A.Name();
 	X = id;
 }
+// this is needed for defining properties named 'action'.
+dottable_id(X) ::= ACTION(A).
+{
+	NEW_AST_NODE(Identifier,id,A);
+	id->Id = NAME_Action;
+	X = id;
+}
 dottable_id(X) ::= dottable_id(A) DOT IDENTIFIER(B).
 {
 	NEW_AST_NODE(Identifier,id2,A);
diff --git a/src/common/scripting/vm/vm.h b/src/common/scripting/vm/vm.h
index 3766e9d31..01e98fb61 100644
--- a/src/common/scripting/vm/vm.h
+++ b/src/common/scripting/vm/vm.h
@@ -194,6 +194,12 @@ struct VMReturn
 		*(void **)Location = val;
 	}
 
+	void SetConstPointer(const void *val)
+	{
+		assert(RegType == REGT_POINTER);
+		*(const void **)Location = val;
+	}
+
 	void SetObject(DObject *val)
 	{
 		assert(RegType == REGT_POINTER);
@@ -759,6 +765,7 @@ struct AFuncDesc
 class AActor;
 
 #define ACTION_RETURN_STATE(v) do { FState *state = v; if (numret > 0) { assert(ret != NULL); ret->SetPointer(state); return 1; } return 0; } while(0)
+#define ACTION_RETURN_CONST_POINTER(v) do { const void *state = v; if (numret > 0) { assert(ret != NULL); ret->SetConstPointer(state); return 1; } return 0; } while(0)
 #define ACTION_RETURN_POINTER(v) do { void *state = v; if (numret > 0) { assert(ret != NULL); ret->SetPointer(state); return 1; } return 0; } while(0)
 #define ACTION_RETURN_OBJECT(v) do { auto state = v; if (numret > 0) { assert(ret != NULL); ret->SetObject(state); return 1; } return 0; } while(0)
 #define ACTION_RETURN_FLOAT(v) do { double u = v; if (numret > 0) { assert(ret != nullptr); ret->SetFloat(u); return 1; } return 0; } while(0)
diff --git a/src/common/textures/textureid.h b/src/common/textures/textureid.h
index e30b4e86a..c441cb9d5 100644
--- a/src/common/textures/textureid.h
+++ b/src/common/textures/textureid.h
@@ -45,7 +45,7 @@ public:
 	bool operator > (FTextureID other) const { return texnum > other.texnum; }
 
 protected:
-	FTextureID(int num) { texnum = num; }
+	constexpr FTextureID(int num) : texnum(num) { }
 private:
 	int texnum;
 };
@@ -53,13 +53,13 @@ private:
 class FNullTextureID : public FTextureID
 {
 public:
-	FNullTextureID() : FTextureID(0) {}
+	constexpr FNullTextureID() : FTextureID(0) {}
 };
 
 // This is for the script interface which needs to do casts from int to texture.
 class FSetTextureID : public FTextureID
 {
 public:
-	FSetTextureID(int v) : FTextureID(v) {}
+	constexpr FSetTextureID(int v) : FTextureID(v) {}
 };
 
diff --git a/src/common/textures/texturemanager.cpp b/src/common/textures/texturemanager.cpp
index 94aa40de1..988498408 100644
--- a/src/common/textures/texturemanager.cpp
+++ b/src/common/textures/texturemanager.cpp
@@ -498,9 +498,9 @@ FTextureID FTextureManager::CreateTexture (int lumpnum, ETextureType usetype)
 //
 //==========================================================================
 
-void FTextureManager::ReplaceTexture (FTextureID picnum, FGameTexture *newtexture, bool free)
+void FTextureManager::ReplaceTexture (FTextureID texid, FGameTexture *newtexture, bool free)
 {
-	int index = picnum.GetIndex();
+	int index = texid.GetIndex();
 	if (unsigned(index) >= Textures.Size())
 		return;
 
diff --git a/src/common/textures/texturemanager.h b/src/common/textures/texturemanager.h
index 575e838ea..3f80514f3 100644
--- a/src/common/textures/texturemanager.h
+++ b/src/common/textures/texturemanager.h
@@ -137,7 +137,7 @@ public:
 	void AddTextures(void (*progressFunc_)(), void (*checkForHacks)(BuildInfo&), void (*customtexturehandler)() = nullptr);
 	void DeleteAll();
 
-	void ReplaceTexture (FTextureID picnum, FGameTexture *newtexture, bool free);
+	void ReplaceTexture (FTextureID texid, FGameTexture *newtexture, bool free);
 
 	int NumTextures () const { return (int)Textures.Size(); }
 
diff --git a/src/common/textures/v_collection.cpp b/src/common/textures/v_collection.cpp
index 2b51885bf..975287680 100644
--- a/src/common/textures/v_collection.cpp
+++ b/src/common/textures/v_collection.cpp
@@ -62,8 +62,8 @@ void FImageCollection::Add (const char **patchNames, int numPatches, ETextureTyp
 
 	for (int i = 0; i < numPatches; ++i)
 	{
-		FTextureID picnum = TexMan.CheckForTexture(patchNames[i], namespc);
-		ImageMap[OldCount + i] = picnum;
+		FTextureID texid = TexMan.CheckForTexture(patchNames[i], namespc);
+		ImageMap[OldCount + i] = texid;
 	}
 }
 
diff --git a/src/common/utility/files.h b/src/common/utility/files.h
index 66fa9a354..24d66e1d7 100644
--- a/src/common/utility/files.h
+++ b/src/common/utility/files.h
@@ -184,7 +184,7 @@ public:
 		return mReader->Seek((long)offset, origin);
 	}
 
-	Size Read(void *buffer, Size len)
+	Size Read(void *buffer, Size len) const
 	{
 		return mReader->Read(buffer, (long)len);
 	}
diff --git a/src/common/utility/tarray.h b/src/common/utility/tarray.h
index 29d62289c..a21226095 100644
--- a/src/common/utility/tarray.h
+++ b/src/common/utility/tarray.h
@@ -327,9 +327,10 @@ public:
 	}
 
 	// returns address of first element
-	T *Data() const
+	T *Data(size_t index = 0) const
 	{
-		return &Array[0];
+		assert(index <= Count);
+		return &Array[index];
 	}
 
 	unsigned IndexOf(const T& elem) const