diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index febcad0b5c..6b963f6d4d 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -60,6 +60,7 @@
 // PRIVATE FUNCTION PROTOTYPES ---------------------------------------------
 
 // EXTERNAL DATA DECLARATIONS ----------------------------------------------
+EXTERN_CVAR(Bool, strictdecorate);
 
 // PUBLIC DATA DEFINITIONS -------------------------------------------------
 
@@ -3067,7 +3068,8 @@ void PClass::InsertIntoHash ()
 	if (found != NULL)
 	{ // This type has already been inserted
 	  // ... but there is no need whatsoever to make it a fatal error!
-		Printf (TEXTCOLOR_RED"Tried to register class '%s' more than once.\n", TypeName.GetChars());
+		if (!strictdecorate) Printf (TEXTCOLOR_RED"Tried to register class '%s' more than once.\n", TypeName.GetChars());
+		else I_Error("Tried to register class '%s' more than once.\n", TypeName.GetChars());
 		TypeTable.ReplaceType(this, found, bucket);
 	}
 	else
diff --git a/src/sc_man.cpp b/src/sc_man.cpp
index dadbae0ed1..da106927e3 100644
--- a/src/sc_man.cpp
+++ b/src/sc_man.cpp
@@ -1038,11 +1038,17 @@ FScriptPosition &FScriptPosition::operator=(const FScriptPosition &other)
 //
 //==========================================================================
 
+CVAR(Bool, strictdecorate, false, CVAR_GLOBALCONFIG|CVAR_ARCHIVE)
+
 void FScriptPosition::Message (int severity, const char *message, ...) const
 {
 	FString composed;
 
 	if ((severity == MSG_DEBUG || severity == MSG_DEBUGLOG) && !developer) return;
+	if (severity == MSG_OPTERROR)
+	{
+		severity = strictdecorate ? MSG_ERROR : MSG_WARNING;
+	}
 
 	if (message == NULL)
 	{
diff --git a/src/sc_man.h b/src/sc_man.h
index b1231e547b..359dd81405 100644
--- a/src/sc_man.h
+++ b/src/sc_man.h
@@ -124,6 +124,7 @@ enum
 	MSG_WARNING,
 	MSG_FATAL,
 	MSG_ERROR,
+	MSG_OPTERROR,
 	MSG_DEBUG,
 	MSG_LOG,
 	MSG_DEBUGLOG,
diff --git a/src/thingdef/thingdef_expression.cpp b/src/thingdef/thingdef_expression.cpp
index 2e60dfa971..d500458a2d 100644
--- a/src/thingdef/thingdef_expression.cpp
+++ b/src/thingdef/thingdef_expression.cpp
@@ -368,8 +368,8 @@ FxExpression *FxIntCast::Resolve(FCompileContext &ctx)
 		else
 		{
 			// Ugh. This should abort, but too many mods fell into this logic hole somewhere, so this seroious error needs to be reduced to a warning. :(
-			if (!basex->isConstant())	ScriptPosition.Message(MSG_WARNING, "Numeric type expected, got a name");
-			else ScriptPosition.Message(MSG_WARNING, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
+			if (!basex->isConstant())	ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got a name");
+			else ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
 			FxExpression * x = new FxConstant(0, ScriptPosition);
 			delete this;
 			return x;
@@ -466,8 +466,8 @@ FxExpression *FxFloatCast::Resolve(FCompileContext &ctx)
 		else
 		{
 			// Ugh. This should abort, but too many mods fell into this logic hole somewhere, so this seroious error needs to be reduced to a warning. :(
-			if (!basex->isConstant()) ScriptPosition.Message(MSG_WARNING, "Numeric type expected, got a name");
-			else ScriptPosition.Message(MSG_WARNING, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
+			if (!basex->isConstant()) ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got a name");
+			else ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
 			FxExpression *x = new FxConstant(0.0, ScriptPosition);
 			delete this;
 			return x;
@@ -3924,7 +3924,7 @@ FxExpression *FxClassTypeCast::Resolve(FCompileContext &ctx)
 			{
 				/* lax */
 				// Since this happens in released WADs it must pass without a terminal error... :(
-				ScriptPosition.Message(MSG_WARNING,
+				ScriptPosition.Message(MSG_OPTERROR,
 					"Unknown class name '%s'",
 					clsname.GetChars(), desttype->TypeName.GetChars());
 			}
@@ -4095,7 +4095,7 @@ FxExpression *FxMultiNameState::Resolve(FCompileContext &ctx)
 			destination = scope->FindState(names.Size()-1, &names[1], false);
 			if (destination == NULL)
 			{
-				ScriptPosition.Message(MSG_WARNING, "Unknown state jump destination");
+				ScriptPosition.Message(MSG_OPTERROR, "Unknown state jump destination");
 				/* lax */
 				return this;
 			}
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index 3ec4c624d5..db6ef14a05 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -457,7 +457,7 @@ DEFINE_PROPERTY(skip_super, 0, Actor)
 	}
 	if (bag.StateSet)
 	{
-		bag.ScriptPosition.Message(MSG_WARNING,
+		bag.ScriptPosition.Message(MSG_OPTERROR,
 			"'skip_super' must appear before any state definitions.");
 		return;
 	}