3 files changed, 32 insertions, 10 deletions
diff --git a/engines/simon/items.cpp b/engines/simon/items.cpp
index 03a7f90527..75c06faf2a 100644
--- a/engines/simon/items.cpp
+++ b/engines/simon/items.cpp
@@ -314,6 +314,7 @@ void SimonEngine::setupOpcodes() {
 		opcode_table[190] = &SimonEngine::o2_waitMark;
 		break;
 	case GType_FF:
+		opcode_table[23] = &SimonEngine::o3_chance;
 		opcode_table[37] = &SimonEngine::o3_jumpOut;
 		opcode_table[65] = &SimonEngine::o3_addTextBox;
 		opcode_table[70] = &SimonEngine::o3_printLongText;
@@ -475,22 +476,22 @@ void SimonEngine::o_chance() {
 		return;
 	}
 
-	a += _scriptUnk1;
+	a += _chanceModifier;
 
 	if (a <= 0) {
-		_scriptUnk1 = 0;
+		_chanceModifier = 0;
 		setScriptCondition(false);
 	} else if ((uint)_rnd.getRandomNumber(99) < a) {
-		if (_scriptUnk1 <= 0)
-			_scriptUnk1 -= 5;
+		if (_chanceModifier <= 0)
+			_chanceModifier -= 5;
 		else
-			_scriptUnk1 = 0;
+			_chanceModifier = 0;
 		setScriptCondition(true);
 	} else {
-		if (_scriptUnk1 >= 0)
-			_scriptUnk1 += 5;
+		if (_chanceModifier >= 0)
+			_chanceModifier += 5;
 		else
-			_scriptUnk1 = 0;
+			_chanceModifier = 0;
 		setScriptCondition(false);
 	}
 }
@@ -1791,6 +1792,26 @@ void SimonEngine::o2_waitMark() {
 // Feeble Files Opcodes
 // -----------------------------------------------------------------------
 
+void SimonEngine::o3_chance() {
+	// 23
+	uint a = getVarOrWord();
+
+	if (a == 0) {
+		setScriptCondition(false);
+		return;
+	}
+
+	if (a == 100) {
+		setScriptCondition(true);
+		return;
+	}
+
+	if ((uint)_rnd.getRandomNumber(99) < a)
+		setScriptCondition(true);
+	else
+		setScriptCondition(false);
+}
+
 void SimonEngine::o3_jumpOut() {
 	// 37
 	getVarOrByte();
diff --git a/engines/simon/simon.cpp b/engines/simon/simon.cpp
index a9f3bed8a3..9adff9ef75 100644
--- a/engines/simon/simon.cpp
+++ b/engines/simon/simon.cpp
@@ -207,7 +207,7 @@ SimonEngine::SimonEngine(OSystem *syst)
 	_oldMouseAnimMax = 0;
 
 	_vgaVar9 = 0;
-	_scriptUnk1 = 0;
+	_chanceModifier = 0;
 	_restoreWindow6 = 0;
 	_scrollX = 0;
 	_scrollY = 0;
diff --git a/engines/simon/simon.h b/engines/simon/simon.h
index 2fd6cf720b..b26156e9de 100644
--- a/engines/simon/simon.h
+++ b/engines/simon/simon.h
@@ -264,7 +264,7 @@ protected:
 	bool _subtitles;
 	bool _fade;
 	bool _vgaVar9;
-	int16 _scriptUnk1;
+	int16 _chanceModifier;
 	bool _restoreWindow6;
 	int _scrollX, _scrollXMax, _scrollWidth;
 	int _scrollY, _scrollYMax, _scrollHeight;
@@ -971,6 +971,7 @@ public:
 	void o2_waitMark();
 
 	// Opcodes, Feeble Files only
+	void o3_chance();
 	void o3_jumpOut();
 	void o3_addTextBox();
 	void o3_printLongText();