diff --git a/sfall/Modules/Objects.cpp b/sfall/Modules/Objects.cpp
index dcb78144..762dd465 100644
--- a/sfall/Modules/Objects.cpp
+++ b/sfall/Modules/Objects.cpp
@@ -29,6 +29,8 @@ namespace sfall
 static int unjamTimeState;
 static int maxCountLoadProto = 512;
 
+static fo::GameObject* outlinedObjs[500];
+
 long Objects::uniqueID = UniqueID::Start; // current counter id, saving to sfallgv.sav
 
 bool Objects::IsUniqueID(long id) {
@@ -251,6 +253,18 @@ skip:
 	}
 }
 
+static __declspec(naked) void obj_render_pre_roof_hack() {
+	__asm {
+		cmp  eax, 500;
+		jge  jbreak;
+		retn;
+jbreak:
+		pop  edx;
+		add  edx, 13; // offset to next section (0x4896E8, 0x4897C7)
+		jmp  edx;
+	}
+}
+
 void Objects::init() {
 	LoadGameHook::OnGameReset() += []() {
 		RestoreObjUnjamAllLocks();
@@ -273,6 +287,15 @@ void Objects::init() {
 
 	// Place some objects on the lower z-layer of the tile
 	MakeCall(0x48D918, obj_insert_hack, 1);
+
+	// Increase the maximum number of objects that can be outlined simultaneously (when w/o HRP 4.x by Mash)
+	if (*(DWORD*)0x48981D == 0x639C00) {
+		// replace _outlinedObjects array (was 100 objects)
+		SafeWriteBatch<DWORD>((DWORD)outlinedObjs - 4, {0x4896DF, 0x4897BE}); // obj_render_pre_roof_
+		SafeWrite32(0x48981D, (DWORD)outlinedObjs); // obj_render_post_roof_
+		// change the maximum limit to 500
+		MakeCalls(obj_render_pre_roof_hack, {0x4896D6, 0x4897B5});
+	}
 }
 
 }
diff --git a/sfall/Modules/Scripting/Handlers/Interface.h b/sfall/Modules/Scripting/Handlers/Interface.h
index 76c647ea..bcde25cf 100644
--- a/sfall/Modules/Scripting/Handlers/Interface.h
+++ b/sfall/Modules/Scripting/Handlers/Interface.h
@@ -27,8 +27,6 @@ namespace script
 
 class OpcodeContext;
 
-void ClearInterfaceArtCache();
-
 // input_functions
 void op_input_funcs_available();
 
diff --git a/sfall/Modules/Scripting/Handlers/Metarule.cpp b/sfall/Modules/Scripting/Handlers/Metarule.cpp
index 12f4fafd..3fac27f2 100644
--- a/sfall/Modules/Scripting/Handlers/Metarule.cpp
+++ b/sfall/Modules/Scripting/Handlers/Metarule.cpp
@@ -126,7 +126,7 @@ static const SfallMetarule metarules[] = {
 	{"loot_obj",                  mf_get_loot_object,           0, 0},
 	{"message_box",               mf_message_box,               1, 4, -1, {ARG_STRING, ARG_INT, ARG_INT, ARG_INT}},
 	{"metarule_exist",            mf_metarule_exist,            1, 1}, // no arg check
-	{"npc_engine_level_up",       mf_npc_engine_level_up,       1, 1},
+	{"npc_engine_level_up",       mf_npc_engine_level_up,       1, 1, -1, {ARG_INT}},
 	{"obj_is_openable",           mf_obj_is_openable,           1, 1,  0, {ARG_OBJECT}},
 	{"obj_under_cursor",          mf_obj_under_cursor,          2, 2,  0, {ARG_INT, ARG_INT}},
 	{"objects_in_radius",         mf_objects_in_radius,         3, 4,  0, {ARG_INT, ARG_INT, ARG_INT, ARG_INT}},
diff --git a/sfall/Modules/Scripting/Handlers/Objects.cpp b/sfall/Modules/Scripting/Handlers/Objects.cpp
index fafab9d7..8e7cf8e8 100644
--- a/sfall/Modules/Scripting/Handlers/Objects.cpp
+++ b/sfall/Modules/Scripting/Handlers/Objects.cpp
@@ -615,7 +615,7 @@ void mf_objects_in_radius(OpcodeContext& ctx) {
 }
 
 void mf_npc_engine_level_up(OpcodeContext& ctx) {
-	if (ctx.arg(0).asBool()) {
+	if (ctx.arg(0).rawValue()) {
 		if (!npcEngineLevelUp) SafeWrite16(0x4AFC1C, 0x840F); // enable
 		npcEngineLevelUp = true;
 	} else {