diff --git a/TetrEnvironment/Info/FallInfo.cs b/TetrEnvironment/Info/FallInfo.cs
index d5b817c..df44cf0 100644
--- a/TetrEnvironment/Info/FallInfo.cs
+++ b/TetrEnvironment/Info/FallInfo.cs
@@ -235,15 +235,23 @@ public void Next(Tetromino.MinoType? newMino)
 
 		if (_manager.GameData.Falling.Ihs)
 		{
+			//TODO: t.setoptions.display_hold && !t.setoptions.display_hold
+			_manager.GameData.Falling.Ihs = false;
 			if (!_manager.GameData.HoldLocked)
 				SwapHold();
 		}
 
 		if (_manager.GameData.Falling.Irs != 0)
-			_manager.HandleInfo.RotatePiece((spawnRotation + _manager.GameData.Falling.Irs) % 14);
+		{
+			_manager.HandleInfo.RotatePiece((spawnRotation + _manager.GameData.Falling.Irs) % 4);
+			_manager.GameData.Falling.Irs = 0;
+		}
 
-		_manager.GameData.Falling.Irs = 0;
-		_manager.GameData.Falling.Ihs = false;
+		if (_manager.GameData.Options.Version >= 17)
+		{
+			if (Is20G())
+				SlamToFloor();
+		}
 	}
 
 	public void SwapHold()
@@ -340,4 +348,26 @@ public Falling.SpinTypeKind IsTspin()
 
 		return spinType;
 	}
+
+	public bool Is20G()
+	{
+		if (_manager.GameData.Options.Version < 17)
+			throw new Exception(
+				"The 20G check should not be called before TETR.IO engine version 17.");
+
+		var boardHeight = _manager.GameData.Options.BoardHeight;
+		if (_manager.GameData.SoftDrop)
+			return _manager.GameData.Handling.SDF == 41 ||
+			       _manager.GameData.Gravity * _manager.GameData.Handling.SDF >= boardHeight;
+		else
+			return _manager.GameData.Gravity >= boardHeight;
+	}
+
+	public void SlamToFloor()
+	{
+		var tempGravity = _manager.GameData.Gravity;
+		_manager.GameData.Gravity = int.MaxValue;
+		FallEvent(null, 1);
+		_manager.GameData.Gravity = tempGravity;
+	}
 }
\ No newline at end of file
diff --git a/TetrEnvironment/Info/HandleInfo.cs b/TetrEnvironment/Info/HandleInfo.cs
index 8bab3da..fad6482 100644
--- a/TetrEnvironment/Info/HandleInfo.cs
+++ b/TetrEnvironment/Info/HandleInfo.cs
@@ -14,11 +14,11 @@ public HandleInfo(Environment manager)
 		_manager = manager;
 	}
 
-	public void KeyDown(EventKeyInputData @event)	
+	public void KeyDown(EventKeyInputData @event)
 	{
 		if ((int)@event.key < 8)
 			_manager.PressingKeys[(int)@event.key] = true;
-		
+
 		if (@event.subframe > _manager.GameData.SubFrame)
 		{
 			_manager.HandleInfo.ProcessShift(false, @event.subframe - _manager.GameData.SubFrame);
@@ -140,7 +140,7 @@ public void KeyUp(EventKeyInputData @event)
 	{
 		if ((int)@event.key < 8)
 			_manager.PressingKeys[(int)@event.key] = false;
-		
+
 		if (@event.subframe > _manager.GameData.SubFrame)
 		{
 			_manager.HandleInfo.ProcessShift(false, @event.subframe - _manager.GameData.SubFrame);
@@ -256,12 +256,13 @@ internal void RotatePiece(int newRotation)
 
 		if (_manager.GameData.Falling.Type == Constants.Tetromino.MinoType.O)
 			return;
-	
-		var kicktable = _manager.Kickset.KICKSET_TABLE[currentNewRotation];
 
+		var kicktable = _manager.Kickset.KICKSET_TABLE[currentNewRotation];
 		if (_manager.GameData.Falling.Type == Constants.Tetromino.MinoType.I)
 			kicktable = _manager.Kickset.KICKSET_TABLE_I[currentNewRotation];
 
+		//if(_manager.GameData.Options.Version<17&&_manager.GameData.Options.kickset=="ARS")
+
 		for (var kicktableIndex = 0; kicktableIndex < kicktable.Length; kicktableIndex++)
 		{
 			var kicktableTest = kicktable[kicktableIndex];
@@ -351,6 +352,9 @@ private void ProcessLShift(bool value, double subFrameDiff = 1)
 				_manager.GameData.Falling.Last = Falling.LastKind.Move;
 				_manager.GameData.Falling.Clamped = false;
 
+				if (_manager.GameData.Options.Version >= 17 && _manager.FallInfo.Is20G())
+					_manager.FallInfo.SlamToFloor();
+
 				if (++_manager.GameData.Falling.LockResets < 15 || _manager.GameData.Options.InfiniteMovement)
 					_manager.GameData.Falling.Locking = 0;
 			}
@@ -404,6 +408,9 @@ private void ProcessRShift(bool value, double subFrameDiff = 1)
 				_manager.GameData.Falling.Last = Falling.LastKind.Move;
 				_manager.GameData.Falling.Clamped = false;
 
+				if (_manager.GameData.Options.Version >= 17 && _manager.FallInfo.Is20G())
+					_manager.FallInfo.SlamToFloor();
+				
 				if (++_manager.GameData.Falling.LockResets < 15 || _manager.GameData.Options.InfiniteMovement)
 					_manager.GameData.Falling.Locking = 0;
 			}
diff --git a/TetrEnvironment/Options.cs b/TetrEnvironment/Options.cs
index dfb9c49..dd89f68 100644
--- a/TetrEnvironment/Options.cs
+++ b/TetrEnvironment/Options.cs
@@ -48,7 +48,7 @@ public class Options
 	public bool Shielded { get; internal set; }
 	public bool HasGarbage { get; internal set; }
 	public int GarbageCapMax { get; internal set; }
-
+	public int BoardHeight { get; internal set; }
 	public bool ClipListenIDs { get; internal set; }
 
 	public Options(EventFullOptionsData fullOptionsData)
@@ -58,7 +58,7 @@ public Options(EventFullOptionsData fullOptionsData)
 		GSpeed = fullOptionsData.gspeed ?? 0.007;
 		LevelSpeed = fullOptionsData.levelspeed ?? 0.42;
 		MasterLevels = fullOptionsData.masterlevels ?? false;
-
+		BoardHeight = fullOptionsData.boardheight ?? 20;
 		Version = fullOptionsData.version;
 		GravityIncrease = fullOptionsData.gincrease ?? 0;
 		GravityMargin = fullOptionsData.gmargin ?? 0;