diff --git a/artifacts/ddraw.ini b/artifacts/ddraw.ini
index 6d95527a..d9cb580e 100644
--- a/artifacts/ddraw.ini
+++ b/artifacts/ddraw.ini
@@ -69,7 +69,7 @@ GraphicsHeight=0
 ;Set to 0 to reset if the window position is incorrect
 WindowData=0
 
-;Uncomment the option to use a hardware shader (requires DX9 graphics mode 4 or 5)
+;Uncomment the option to use a hardware shader (requires DX9 graphics mode)
 ;The shader file <name>.fx must be placed in <GameRoot>\<master_patches>\shaders\ and must contain one technique with one or more passes
 ;GlobalShaderFile=global.fx
 
@@ -87,7 +87,7 @@ GPUBlt=0
 Use32BitHeadGraphics=0
 
 ;Set to 1 to automatically search for alternative avi video files when Fallout tries to play the game movies
-;Requires DX9 graphics mode 4 or 5
+;Requires DX9 graphics mode
 AllowDShowMovies=0
 
 ;Fade effect time percentage modifier
@@ -160,7 +160,7 @@ SpeedKey7=0x00
 SpeedKey8=0x00
 SpeedKey9=0x00
 
-;A key to hold down to move the window around when using graphics mode 5
+;A key to hold down to move the window around when using DX9 graphics mode 5
 ;Set to 0 if you don't want to use a modifier key, or a DX scancode otherwise
 ;Set to -1 for either ctrl key, -2 for either alt key or -3 for either shift key
 WindowScrollKey=0
diff --git a/sfall/BugFixes.cpp b/sfall/BugFixes.cpp
index e9ecf244..2c68e289 100644
--- a/sfall/BugFixes.cpp
+++ b/sfall/BugFixes.cpp
@@ -3246,9 +3246,6 @@ void BugFixesInit()
 	// Place the player on a nearby empty tile if the entrance tile is blocked by another object when entering a map
 	HookCall(0x4836F8, map_check_state_hook);
 
-	// Remove duplicate code from intface_redraw_ engine function
-	BlockCall(0x45EBBF);
-
 	// Fix for critter_add/rm_trait functions ignoring the value of the "amount" argument
 	// Note: pass negative amount values to critter_rm_trait to remove all ranks of the perk (vanilla behavior)
 	HookCall(0x458CDB, op_critter_rm_trait_hook);
diff --git a/sfall/DebugEditor.cpp b/sfall/DebugEditor.cpp
index c9b6395d..f2431e60 100644
--- a/sfall/DebugEditor.cpp
+++ b/sfall/DebugEditor.cpp
@@ -343,16 +343,6 @@ static void __declspec(naked) debug_log_hack() {
 	}
 }
 
-static void __declspec(naked) op_display_msg_hook() {
-	__asm {
-		cmp  dword ptr ds:_debug_func, 0;
-		jne  debug;
-		retn;
-debug:
-		jmp  config_get_value_;
-	}
-}
-
 static void DebugModePatch() {
 	int dbgMode = iniGetInt("Debugging", "DebugMode", 0, ddrawIniDef);
 	if (dbgMode > 0) {
@@ -393,8 +383,6 @@ static void DebugModePatch() {
 
 		dlogr(" Done", DL_INIT);
 	}
-	// Just for speeding up display_msg function (optional)
-	HookCall(0x455404, op_display_msg_hook);
 }
 
 static void DontDeleteProtosPatch() {
diff --git a/sfall/FalloutEngine.cpp b/sfall/FalloutEngine.cpp
index 54723c1d..ef5dcc7b 100644
--- a/sfall/FalloutEngine.cpp
+++ b/sfall/FalloutEngine.cpp
@@ -881,6 +881,10 @@ void __stdcall GsoundPlaySfxFile(const char* name) {
 	WRAP_WATCOM_CALL1(gsound_play_sfx_file_, name)
 }
 
+bool __stdcall ArtExists(long artFid) {
+	WRAP_WATCOM_CALL1(art_exists_, artFid)
+}
+
 // Returns the name of the critter
 const char* __stdcall CritterName(TGameObj* critter) {
 	WRAP_WATCOM_CALL1(critter_name_, critter)
@@ -1508,6 +1512,10 @@ long __stdcall ArtPtrUnlock(DWORD lockId) {
 	WRAP_WATCOM_CALL1(art_ptr_unlock_, lockId)
 }
 
+long __stdcall LightGetTile(long elevation, long tileNum) {
+	WRAP_WATCOM_CALL2(light_get_tile_, elevation, tileNum)
+}
+
 long __stdcall LoadFrame(const char* filename, FrmFile** frmPtr) {
 	WRAP_WATCOM_CALL2(load_frame_, filename, frmPtr)
 }
diff --git a/sfall/FalloutEngine.h b/sfall/FalloutEngine.h
index 4dc9ebb6..6eb0dfe3 100644
--- a/sfall/FalloutEngine.h
+++ b/sfall/FalloutEngine.h
@@ -1073,6 +1073,8 @@ long __stdcall GetInputBtn();
 // plays SFX sound with given name
 void __stdcall GsoundPlaySfxFile(const char* name);
 
+bool __stdcall ArtExists(long artFid);
+
 // Returns the name of the critter
 const char* __stdcall CritterName(TGameObj* critter);
 
@@ -1325,6 +1327,9 @@ BYTE* __stdcall ArtLock(long frmId, DWORD* lockPtr, long* widthOut, long* height
 
 long __stdcall ArtPtrUnlock(DWORD lockId);
 
+// returns light level at given tile
+long __stdcall LightGetTile(long elevation, long tileNum);
+
 long __stdcall LoadFrame(const char* filename, FrmFile** frmPtr);
 
 long __stdcall FMtextWidth(const char* text);
diff --git a/sfall/PartyControl.cpp b/sfall/PartyControl.cpp
index 75c62181..7614425d 100644
--- a/sfall/PartyControl.cpp
+++ b/sfall/PartyControl.cpp
@@ -260,14 +260,7 @@ int __fastcall PartyControl_SwitchHandHook(TGameObj* item) {
 		int fId = *ptr_i_fid; //(*ptr_obj_dude)->artFid;
 		char weaponCode = AnimCodeByWeapon(item);
 		fId = (fId & 0xFFFF0FFF) | (weaponCode << 12);
-		// check if art with this weapon exists
-		int canUse;
-		__asm {
-			mov eax, fId;
-			call art_exists_;
-			mov canUse, eax;
-		}
-		if (!canUse) {
+		if (!ArtExists(fId)) {
 			DisplayCantDoThat();
 			return 1;
 		}
@@ -313,8 +306,8 @@ gonormal:
 }
 
 // hack to exit from this function safely when you load game during NPC turn
-static const DWORD CombatHack_add_noncoms_back = 0x422359;
 static void __declspec(naked) CombatHack_add_noncoms_() {
+	static const DWORD CombatHack_add_noncoms_back = 0x422359;
 	__asm {
 		call CombatWrapper_v2;
 		cmp eax, -1;
diff --git a/sfall/ScriptExtender.cpp b/sfall/ScriptExtender.cpp
index 85ce9f68..55f99c8e 100644
--- a/sfall/ScriptExtender.cpp
+++ b/sfall/ScriptExtender.cpp
@@ -630,7 +630,7 @@ static void __declspec(naked) GetSfallArg() {
 		call GetHSArg;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
@@ -669,7 +669,7 @@ static void __declspec(naked) GetSfallArgs() {
 		call GetSfallArgs2;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
diff --git a/sfall/ScriptOps/AnimOps.hpp b/sfall/ScriptOps/AnimOps.hpp
index 471dae2d..bcfce4a2 100644
--- a/sfall/ScriptOps/AnimOps.hpp
+++ b/sfall/ScriptOps/AnimOps.hpp
@@ -199,29 +199,27 @@ static void __declspec(naked) op_reg_anim_callback() {
 	_WRAP_OPCODE(op_reg_anim_callback2, 1, 0)
 }
 
+static void _stdcall op_explosions_metarule2() {
+	const ScriptValue &modeArg = opHandler.arg(0),
+					  &arg1Arg = opHandler.arg(1),
+					  &arg2Arg = opHandler.arg(2);
+
+	if (modeArg.isInt() && arg1Arg.isInt() && arg2Arg.isInt()) {
+		int mode = modeArg.rawValue(),
+			result = ExplosionsMetaruleFunc(mode, arg1Arg.rawValue(), arg2Arg.rawValue());
+
+		if (result == -1) {
+			opHandler.printOpcodeError("metarule2_explosions() - mode (%d) is not supported for the function.", mode);
+		}
+		opHandler.setReturn(result);
+	} else {
+		OpcodeInvalidArgs("metarule2_explosions");
+		opHandler.setReturn(-1);
+	}
+}
+
 static void __declspec(naked) op_explosions_metarule() {
-	_OP_BEGIN(ebp)
-	_GET_ARG_R32(ebp, ebx, esi) // arg3
-	_GET_ARG_R32(ebp, ecx, edi) // arg2
-	_GET_ARG_R32(ebp, edx, eax) // arg1
-	// eax should not change until function call
-	_CHECK_ARG_INT(bx, fail)
-	_CHECK_ARG_INT(cx, fail)
-	_CHECK_ARG_INT(dx, fail)
-	__asm {
-		push esi
-		push edi
-		push eax
-		call ExplosionsMetaruleFunc;
-		jmp end;
-	}
-fail:
-	__asm {
-		mov eax, -1
-	}
-end:
-	_RET_VAL_INT(ebp)
-	_OP_END
+	_WRAP_OPCODE(op_explosions_metarule2, 3, 1)
 }
 
 static void sf_art_cache_flush() {
diff --git a/sfall/ScriptOps/AsmMacros.h b/sfall/ScriptOps/AsmMacros.h
index 77afd35b..f5e025d4 100644
--- a/sfall/ScriptOps/AsmMacros.h
+++ b/sfall/ScriptOps/AsmMacros.h
@@ -113,7 +113,7 @@ __asm skipgetstr##num:					\
 notstring##num:
 
 // must be immediately after C function call
-#define _RET_VAL_INT(rscript) __asm {		\
+#define _RET_VAL_INT32(rscript) __asm {		\
 	__asm mov edx, eax					\
 	__asm mov eax, rscript				\
 	__asm call interpretPushLong_		\
@@ -137,7 +137,7 @@ notstring##num:
 	eax and ebx register must contain the script_ptr
 	edx register must contain the returned value
 */
-#define _RET_VAL_INT2 __asm {			\
+#define _RET_VAL_INT __asm {			\
 	__asm call interpretPushLong_		\
 	__asm mov  edx, VAR_TYPE_INT		\
 	__asm mov  eax, ebx					\
diff --git a/sfall/ScriptOps/GraphicsOps.hpp b/sfall/ScriptOps/GraphicsOps.hpp
index e494c1c8..db47b0f8 100644
--- a/sfall/ScriptOps/GraphicsOps.hpp
+++ b/sfall/ScriptOps/GraphicsOps.hpp
@@ -397,7 +397,7 @@ static void __declspec(naked) funcGetShaderVersion() {
 		call GetShaderVersion;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
diff --git a/sfall/ScriptOps/MemoryOps.hpp b/sfall/ScriptOps/MemoryOps.hpp
index c107ef8b..7a097618 100644
--- a/sfall/ScriptOps/MemoryOps.hpp
+++ b/sfall/ScriptOps/MemoryOps.hpp
@@ -38,7 +38,7 @@ result:
 //		retn;
 error:
 		xor  edx, edx;
-		jmp result;
+		jmp  result;
 	}
 }
 
@@ -54,7 +54,7 @@ result:
 //		retn;
 error:
 		xor  edx, edx;
-		jmp result;
+		jmp  result;
 	}
 }
 
@@ -70,7 +70,7 @@ result:
 //		retn;
 error:
 		xor  edx, edx;
-		jmp result;
+		jmp  result;
 	}
 }
 
@@ -251,7 +251,7 @@ static void __fastcall CallOffsetInternal(TProgram* script, DWORD func) {
 			mov eax, script;
 			mov edx, args[0];
 			mov ebx, eax;
-			_RET_VAL_INT2;
+			_RET_VAL_INT;
 		}
 	}
 }
diff --git a/sfall/ScriptOps/MiscOps.hpp b/sfall/ScriptOps/MiscOps.hpp
index c77e6ba9..bad27da2 100644
--- a/sfall/ScriptOps/MiscOps.hpp
+++ b/sfall/ScriptOps/MiscOps.hpp
@@ -132,7 +132,7 @@ static void __declspec(naked) GameLoaded() {
 		call ScriptHasLoaded;
 		movzx edx, al;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
@@ -170,7 +170,7 @@ skip:
 		mov  edx, ds:[_pc_kill_counts][eax * 4];
 end:
 		mov  eax, ebx; // script
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		retn;
 fail:
 		xor  edx, edx; // return 0
@@ -588,7 +588,7 @@ static void __declspec(naked) funcGetTickCount() {
 		call GetTickCount2;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
@@ -943,7 +943,7 @@ static void __declspec(naked) get_tile_fid() {
 		mov  ebx, esi; // script
 end:
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		pop  ecx;
 		retn;
 fail:
@@ -1095,27 +1095,25 @@ static void __declspec(naked) op_sneak_success() {
 	__asm {
 		call is_pc_sneak_working_
 	}
-	_RET_VAL_INT(ebp)
+	_RET_VAL_INT32(ebp)
 	_OP_END
 }
 
-static void __declspec(naked) op_tile_light() {
-	_OP_BEGIN(ebp)
-	_GET_ARG_R32(ebp, ebx, edi)  // arg2 - tile
-	_GET_ARG_R32(ebp, ecx, esi)  // arg1 - elevation
-	_CHECK_ARG_INT(bx, fail)
-	_CHECK_ARG_INT(cx, fail)
-	__asm {
-		mov eax, esi
-		mov edx, edi
-		call light_get_tile_
-		jmp end
-fail:
-		mov eax, -1
-end:
+static void _stdcall op_tile_light2() {
+	const ScriptValue &elevArg = opHandler.arg(0),
+					  &tileArg = opHandler.arg(1);
+
+	if (elevArg.isInt() && tileArg.isInt()) {
+		int lightLevel = LightGetTile(elevArg.rawValue(), tileArg.rawValue());
+		opHandler.setReturn(lightLevel);
+	} else {
+		OpcodeInvalidArgs("tile_light");
+		opHandler.setReturn(-1);
 	}
-	_RET_VAL_INT(ebp)
-	_OP_END
+}
+
+static void __declspec(naked) op_tile_light() {
+	_WRAP_OPCODE(op_tile_light2, 2, 1)
 }
 
 static void sf_exec_map_update_scripts() {
diff --git a/sfall/ScriptOps/ObjectsOps.hpp b/sfall/ScriptOps/ObjectsOps.hpp
index ea7ec616..8c017563 100644
--- a/sfall/ScriptOps/ObjectsOps.hpp
+++ b/sfall/ScriptOps/ObjectsOps.hpp
@@ -456,7 +456,7 @@ fail:
 		xor eax, eax;
 end:
 	}
-	_RET_VAL_INT(ebp)
+	_RET_VAL_INT32(ebp)
 	_OP_END
 }
 
diff --git a/sfall/ScriptOps/ScriptArrays.hpp b/sfall/ScriptOps/ScriptArrays.hpp
index 3ba19287..e426e22f 100644
--- a/sfall/ScriptOps/ScriptArrays.hpp
+++ b/sfall/ScriptOps/ScriptArrays.hpp
@@ -432,7 +432,7 @@ static void __declspec(naked) op_load_array() {
 		push ecx; // arg 1: key
 		call LoadArray;
 	}
-	_RET_VAL_INT(ebp)
+	_RET_VAL_INT32(ebp)
 	_OP_END
 }
 
@@ -457,7 +457,7 @@ static void __declspec(naked) op_get_array_key() {
 wrongarg:
 		xor eax, eax; // return 0 on wrong arguments
 	}
-	_RET_VAL_INT(ebp)
+	_RET_VAL_INT32(ebp)
 end:
 	_OP_END
 }
@@ -482,7 +482,7 @@ static void __declspec(naked) op_stack_array() {
 		push edi // arg 1: key
 		call StackArray
 	}
-	_RET_VAL_INT(ebp)
+	_RET_VAL_INT32(ebp)
 	_OP_END
 }
 
diff --git a/sfall/ScriptOps/WorldmapOps.hpp b/sfall/ScriptOps/WorldmapOps.hpp
index 41d52e62..90380305 100644
--- a/sfall/ScriptOps/WorldmapOps.hpp
+++ b/sfall/ScriptOps/WorldmapOps.hpp
@@ -122,7 +122,7 @@ static void __declspec(naked) funcInWorldMap() {
 		call InWorldMap;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
@@ -134,7 +134,7 @@ static void __declspec(naked) GetGameMode() {
 		call GetLoopFlags;
 		mov  edx, eax;
 		mov  eax, ebx;
-		_RET_VAL_INT2;
+		_RET_VAL_INT;
 		mov  ecx, esi;
 		retn;
 	}
diff --git a/sfall/main.cpp b/sfall/main.cpp
index 280967cc..a0a9b01f 100644
--- a/sfall/main.cpp
+++ b/sfall/main.cpp
@@ -331,6 +331,16 @@ playWalkMovie:
 	}
 }
 
+static void __declspec(naked) op_display_msg_hook() {
+	__asm {
+		cmp  dword ptr ds:_debug_func, 0;
+		jne  debug;
+		retn;
+debug:
+		jmp  config_get_value_;
+	}
+}
+
 static void DllMain2() {
 	long tmp;
 	dlogr("In DllMain2", DL_MAIN);
@@ -484,6 +494,27 @@ static void DllMain2() {
 	dlogr("Running HeroAppearanceModInit().", DL_INIT);
 	HeroAppearanceModInit();
 
+	/////////////////// Engine Optimization Patches ////////////////////
+
+	// Speed up display_msg script function
+	HookCall(0x455404, op_display_msg_hook);
+
+	// Remove duplicate code from intface_redraw_ engine function
+	BlockCall(0x45EBBF);
+
+	// Improve performance of the data conversion of script interpreter
+	// mov eax, [edx+eax]; bswap eax; ret;
+	SafeWrite32(0x4672A4, 0x0F02048B);
+	SafeWrite16(0x4672A8, 0xC3C8);
+	// mov eax, [edx+eax]; bswap eax;
+	SafeWrite32(0x4673E5, 0x0F02048B);
+	SafeWrite8(0x4673E9, 0xC8);
+	// mov ax, [eax]; rol ax, 8; ret;
+	SafeWrite32(0x467292, 0x66008B66);
+	SafeWrite32(0x467296, 0xC308C0C1);
+
+	////////////////////////////////////////////////////////////////////
+
 	if (GetConfigString("Misc", "StartingMap", "", mapName, 64)) {
 		dlog("Applying starting map patch.", DL_INIT);
 		SafeWrite32(0x480AAA, (DWORD)&mapName);