diff --git a/source/enemy/ngary.cpp b/source/enemy/ngary.cpp
index a84957740..f12866375 100644
--- a/source/enemy/ngary.cpp
+++ b/source/enemy/ngary.cpp
@@ -25,14 +25,20 @@ void CNpc::processGaryMovement( int _frames )
 	s8 multiplier = -1 + ( 2 * m_extension );
 	s32 maxHeight = 10;
 	s32 fallSpeed = 5;
+	s8 yMovement = fallSpeed * _frames;
+	s8 groundHeight;
 
 	// check vertical collision
 
-	if ( isCollisionWithGround() )
+	groundHeight = m_layerCollision->getHeightFromGround( Pos.vx, Pos.vy, yMovement + 16 );
+
+	if ( groundHeight <= 0 )
 	{
+		// groundHeight <= 0  indicates either on ground or below ground
+
 		// check horizontal collision
 
-		if ( m_layerCollision->Get( ( Pos.vx + ( multiplier * _frames ) ) >> 4, ( Pos.vy - maxHeight ) >> 4 ) )
+		if ( m_layerCollision->getHeightFromGround( Pos.vx + ( multiplier * _frames ), Pos.vy ) < -maxHeight )
 		{
 			// reverse direction
 
@@ -40,50 +46,37 @@ void CNpc::processGaryMovement( int _frames )
 		}
 		else
 		{
-			s32 distY;
-			s32 lastPointY = 0;
+			// make sure we are on the ground, not below it
 
-			for ( distY = 0 ; distY <= maxHeight ; distY++ )
-			{
-				if ( !m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy - distY ) >> 4 ) )
-				{
-					break;
-				}
-				else
-				{
-					lastPointY--;
-				}
-			}
-
-			Pos.vy += lastPointY;
+			Pos.vy += groundHeight;
 
 			Pos.vx += multiplier * _frames;
 		}
 	}
 	else
 	{
-		if ( m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + ( fallSpeed * _frames ) ) >> 4 ) )
+		// above ground
+
+		if ( groundHeight < yMovement )
 		{
-			s32 distY;
-			s32 lastPointY = 0;
+			// colliding with ground
 
-			for ( distY = 1 ; distY <= _frames ; distY++ )
+			Pos.vy += groundHeight;
+
+			if ( m_layerCollision->getHeightFromGround( Pos.vx + ( multiplier * _frames ), Pos.vy ) < -maxHeight )
 			{
-				if ( m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + distY ) >> 4 ) )
-				{
-					break;
-				}
-				else
-				{
-					lastPointY++;
-				}
-			}
+				// reverse direction
 
-			Pos.vy += lastPointY;
+				m_extension = !m_extension;
+			}
+			else
+			{
+				Pos.vx += multiplier * _frames;
+			}
 		}
 		else
 		{
-			Pos.vy += fallSpeed * _frames;
+			Pos.vy += yMovement;
 		}
 	}
 }
\ No newline at end of file
diff --git a/source/enemy/ngeneric.cpp b/source/enemy/ngeneric.cpp
index 743dd9d47..be63a7c80 100644
--- a/source/enemy/ngeneric.cpp
+++ b/source/enemy/ngeneric.cpp
@@ -102,5 +102,5 @@ void CNpc::processGenericGetUserDist( int _frames, s32 *distX, s32 *distY )
 bool CNpc::isCollisionWithGround()
 {
 	ASSERT(m_layerCollision);
-	return m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + 1 ) >>4 );
+	return m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + 1 ) >> 4 ) ? 16:0;
 }
diff --git a/source/enemy/npc.cpp b/source/enemy/npc.cpp
index 3e4991a5e..9966218d5 100644
--- a/source/enemy/npc.cpp
+++ b/source/enemy/npc.cpp
@@ -54,7 +54,7 @@ class CLayerCollision	*CNpc::m_layerCollision;
 
 void CNpc::init()
 {
-	m_type = NPC_FALLING_ITEM;
+	m_type = NPC_GARY;
 
 	m_heading = m_fireHeading = 0;
 	m_movementTimer = 0;
diff --git a/source/enemy/nsstomp.cpp b/source/enemy/nsstomp.cpp
index 277abfc27..816157034 100644
--- a/source/enemy/nsstomp.cpp
+++ b/source/enemy/nsstomp.cpp
@@ -26,6 +26,9 @@
 
 void CNpc::processCloseSkullStomperAttack( int _frames )
 {
+	s8 groundHeight;
+	s8 yMovement;
+
 	if ( m_timerTimer > 0 )
 	{
 		// wait
@@ -34,26 +37,15 @@ void CNpc::processCloseSkullStomperAttack( int _frames )
 	{
 		if ( m_extendDir == EXTEND_DOWN )
 		{
-			if ( m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + ( m_data[m_type].speed * _frames ) ) >> 4 ) )
+			yMovement = m_data[m_type].speed * _frames;
+
+			groundHeight = m_layerCollision->getHeightFromGround( Pos.vx, Pos.vy, yMovement + 16 );
+
+			if ( groundHeight < yMovement )
 			{
 				// colliding with ground
 
-				s32 distY;
-				s32 lastPointY = 0;
-
-				for ( distY = 1 ; distY <= ( m_data[m_type].speed * _frames ) ; distY++ )
-				{
-					if ( m_layerCollision->Get( Pos.vx >> 4, ( Pos.vy + distY ) >> 4 ) )
-					{
-						break;
-					}
-					else
-					{
-						lastPointY++;
-					}
-				}
-
-				Pos.vy += lastPointY;
+				Pos.vy += groundHeight;
 
 				// pause and change direction
 
@@ -64,7 +56,7 @@ void CNpc::processCloseSkullStomperAttack( int _frames )
 			{
 				// drop down
 
-				Pos.vy += m_data[m_type].speed * _frames;
+				Pos.vy += yMovement;
 			}
 		}
 		else