diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 2720f026d..9e64f1d29 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -837,9 +837,6 @@ set( NOT_COMPILED_SOURCE_FILES
 	sc_man_scanner.re
 	g_doom/a_archvile.cpp
 	g_doom/a_bossbrain.cpp
-	g_doom/a_bruiser.cpp
-	g_doom/a_cacodemon.cpp
-	g_doom/a_cyberdemon.cpp
 	g_doom/a_demon.cpp
 	g_doom/a_doomimp.cpp
 	g_doom/a_doomweaps.cpp
diff --git a/src/scripting/thingdef.h b/src/scripting/thingdef.h
index a8c9b0b9b..44a441bee 100644
--- a/src/scripting/thingdef.h
+++ b/src/scripting/thingdef.h
@@ -24,7 +24,7 @@ struct FFlagDef
 	const char *name;
 	int structoffset;
 	int fieldsize;
-	bool deprecated;
+	int varflags;
 };
 
 FFlagDef *FindFlag (const PClass *type, const char *part1, const char *part2, bool strict = false);
diff --git a/src/scripting/thingdef_data.cpp b/src/scripting/thingdef_data.cpp
index 063b6e204..4622e764c 100644
--- a/src/scripting/thingdef_data.cpp
+++ b/src/scripting/thingdef_data.cpp
@@ -54,11 +54,12 @@ static TArray<AFuncDesc> AFTable;
 //==========================================================================
 
 // [RH] Keep GCC quiet by not using offsetof on Actor types.
-#define DEFINE_FLAG(prefix, name, type, variable) { (unsigned int)prefix##_##name, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), false }
-#define DEFINE_FLAG2(symbol, name, type, variable) { (unsigned int)symbol, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), false }
-#define DEFINE_FLAG2_DEPRECATED(symbol, name, type, variable) { (unsigned int)symbol, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), true }
+#define DEFINE_FLAG(prefix, name, type, variable) { (unsigned int)prefix##_##name, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), VARF_Native }
+#define DEFINE_READONLY_FLAG(prefix, name, type, variable) { (unsigned int)prefix##_##name, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), VARF_Native|VARF_ReadOnly }
+#define DEFINE_FLAG2(symbol, name, type, variable) { (unsigned int)symbol, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), VARF_Native }
+#define DEFINE_FLAG2_DEPRECATED(symbol, name, type, variable) { (unsigned int)symbol, #name, (int)(size_t)&((type*)1)->variable - 1, sizeof(((type *)0)->variable), VARF_Native|VARF_Deprecated }
 #define DEFINE_DEPRECATED_FLAG(name) { DEPF_##name, #name, -1, 0, true }
-#define DEFINE_DUMMY_FLAG(name, deprec) { DEPF_UNUSED, #name, -1, 0, deprec }
+#define DEFINE_DUMMY_FLAG(name, deprec) { DEPF_UNUSED, #name, -1, 0, deprec? VARF_Deprecated:0 }
 
 static FFlagDef ActorFlagDefs[]=
 {
@@ -66,8 +67,8 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF, SPECIAL, APlayerPawn, flags),
 	DEFINE_FLAG(MF, SOLID, AActor, flags),
 	DEFINE_FLAG(MF, SHOOTABLE, AActor, flags),
-	DEFINE_FLAG(MF, NOSECTOR, AActor, flags),
-	DEFINE_FLAG(MF, NOBLOCKMAP, AActor, flags),
+	DEFINE_READONLY_FLAG(MF, NOSECTOR, AActor, flags),
+	DEFINE_READONLY_FLAG(MF, NOBLOCKMAP, AActor, flags),
 	DEFINE_FLAG(MF, AMBUSH, AActor, flags),
 	DEFINE_FLAG(MF, JUSTHIT, AActor, flags),
 	DEFINE_FLAG(MF, JUSTATTACKED, AActor, flags),
@@ -83,8 +84,8 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF, NOBLOOD, AActor, flags),
 	DEFINE_FLAG(MF, CORPSE, AActor, flags),
 	DEFINE_FLAG(MF, INFLOAT, AActor, flags),
-	DEFINE_FLAG(MF, COUNTKILL, AActor, flags),
-	DEFINE_FLAG(MF, COUNTITEM, AActor, flags),
+	DEFINE_READONLY_FLAG(MF, COUNTKILL, AActor, flags),
+	DEFINE_READONLY_FLAG(MF, COUNTITEM, AActor, flags),
 	DEFINE_FLAG(MF, SKULLFLY, AActor, flags),
 	DEFINE_FLAG(MF, NOTDMATCH, AActor, flags),
 	DEFINE_FLAG(MF, SPAWNSOUNDSOURCE, AActor, flags),
@@ -185,7 +186,7 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF5, GETOWNER, AActor, flags5),
 	DEFINE_FLAG(MF5, NODROPOFF, AActor, flags5),
 	DEFINE_FLAG(MF5, NOFORWARDFALL, AActor, flags5),
-	DEFINE_FLAG(MF5, COUNTSECRET, AActor, flags5),
+	DEFINE_READONLY_FLAG(MF5, COUNTSECRET, AActor, flags5),
 	DEFINE_FLAG(MF5, NODAMAGE, AActor, flags5),
 	DEFINE_FLAG(MF5, BLOODSPLATTER, AActor, flags5),
 	DEFINE_FLAG(MF5, OLDRADIUSDMG, AActor, flags5),
@@ -696,7 +697,7 @@ void InitThingdef()
 		int bit = 0;
 		unsigned val = ActorFlagDefs[i].flagbit;
 		while ((val >>= 1)) bit++;
-		symt.AddSymbol(new PField(FStringf("b%s", ActorFlagDefs[i].name), (ActorFlagDefs[i].fieldsize == 4? TypeSInt32 : TypeSInt16), VARF_Native, ActorFlagDefs[i].structoffset, bit));
+		symt.AddSymbol(new PField(FStringf("b%s", ActorFlagDefs[i].name), (ActorFlagDefs[i].fieldsize == 4? TypeSInt32 : TypeSInt16), ActorFlagDefs[i].varflags, ActorFlagDefs[i].structoffset, bit));
 	}
 
 }
diff --git a/src/scripting/zscript/zcc_compile.cpp b/src/scripting/zscript/zcc_compile.cpp
index 49ba68f0a..22107796f 100644
--- a/src/scripting/zscript/zcc_compile.cpp
+++ b/src/scripting/zscript/zcc_compile.cpp
@@ -1836,7 +1836,7 @@ void ZCCCompiler::ProcessDefaultFlag(PClassActor *cls, ZCC_FlagStmt *flg)
 	auto fd = FindFlag(cls, n1, n2, true);
 	if (fd != nullptr)
 	{
-		if (fd->deprecated)
+		if (fd->varflags & VARF_Deprecated)
 		{
 			Warn(flg, "Deprecated flag '%s%s%s' used", n1, n2 ? "." : "", n2 ? n2 : "");
 		}