diff --git a/Platform/Apple/tools/PackPartitions/src/org/demo/PackPartitions.groovy b/Platform/Apple/tools/PackPartitions/src/org/demo/PackPartitions.groovy
index 0303dd03..b5b76435 100644
--- a/Platform/Apple/tools/PackPartitions/src/org/demo/PackPartitions.groovy
+++ b/Platform/Apple/tools/PackPartitions/src/org/demo/PackPartitions.groovy
@@ -431,18 +431,15 @@ class PackPartitions
                     if (name == null || name.toLowerCase() =~ /street|blank|null/)
                         texMap[id] = 0
                     else if (stripName(name) in textures) {
-                        def flags = 0
+                        def flags = 1
                         if (tile?.@obstruction == 'true')
-                            flags |= 1
-                        if (tile?.@sprite == 'true')
                             flags |= 2
                         if (tile?.@blocker == 'true')
                             flags |= 4
                         texList.add(textures[stripName(name)].num)
                         texFlags.add(flags)
                         texMap[id] = texList.size()
-                        println "tex #${texList.size()}: name=$name flags=$flags"
-                        if (tile?.@obstruction != 'true')
+                        if (tile?.@sprite == 'true')
                             texMap[id] |= 0x80; // hi-bit flag to mark sprite cells
                     }
                     else if (id) {
@@ -464,6 +461,10 @@ class PackPartitions
         texList.each { buf.put((byte)it) }
         buf.put((byte)0)
         
+        // Followed by the corresponding list of texture flags
+        texFlags.each { buf.put((byte)it) }
+        buf.put((byte)0)
+        
         // Sentinel row of $FF at start of map
         (0..<width).each { buf.put((byte)0xFF) }
         
diff --git a/Platform/Apple/virtual/src/plasma/gameloop.pla b/Platform/Apple/virtual/src/plasma/gameloop.pla
index 8bd9d8ca..dc880e61 100644
--- a/Platform/Apple/virtual/src/plasma/gameloop.pla
+++ b/Platform/Apple/virtual/src/plasma/gameloop.pla
@@ -132,8 +132,8 @@ byte              = $22 ; blue
 byte              = $28 ; orange
 byte              = $2A ; hi-bit white
 
-word skyNum = 0
-word groundNum = 0
+word skyNum = 9
+word groundNum = 10
 
 ;==================================================================================================
 ; Definitions used by assembly code
@@ -367,9 +367,11 @@ def initCmd(key, func)
 end
 
 def moveForward()
+  word wasBlocked 
+  wasBlocked = isBlocked()
   *playerX = *playerX + walkDirs[^playerDir * 2]
   *playerY = *playerY + walkDirs[^playerDir * 2 + 1]
-  if isBlocked()
+  if !wasBlocked and isBlocked()
     moveBackward()
   fin
 end
@@ -379,10 +381,12 @@ def adjustDir(n)
 end
 
 def moveBackward()
+  word wasBlocked 
+  wasBlocked = isBlocked()
   adjustDir(8)
   moveForward()
   adjustDir(8)
-  if isBlocked()
+  if !wasBlocked and isBlocked()
     moveForward()
   fin
 end
diff --git a/Platform/Apple/virtual/src/raycast/render.s b/Platform/Apple/virtual/src/raycast/render.s
index ba8f4af3..c6bdf6ff 100644
--- a/Platform/Apple/virtual/src/raycast/render.s
+++ b/Platform/Apple/virtual/src/raycast/render.s
@@ -11,7 +11,7 @@ start:
 ; code is at the very end. We jump to it now.
 	jmp initMap
 	jmp renderFrame
-	jmp getMapCell
+	jmp isBlocked
 	jmp setColor
 
 ; Conditional assembly flags
@@ -19,9 +19,6 @@ DOUBLE_BUFFER	= 1		; whether to double-buffer
 DEBUG		= 0		; 1=some logging, 2=lots of logging
 DEBUG_COLUMN	= -1
 
-; temporary hack to try blocker sprites
-BLOCKER_FOO	= 0
-
 ; Shared constants, zero page, buffer locations, etc.
 !source "render.i"
 ; Debug macros and support functions
@@ -390,14 +387,19 @@ castRay: !zone
 .hitSprite:
 	cmp #$FF		; check for special mark at edges of map
 	beq .hitEdge
-!if BLOCKER_FOO {
-	cmp #$c1
-	beq .hitEdge
-}
 	; We found a sprite cell on the map. We only want to process this sprite once,
 	; so check if we've already done it.
+	tax
 	and #$40
-	bne .spriteDone		; already done, don't do again
+	beq .notDone		; already done, don't do again
+	txa
+	and #$3F
+	tax
+	jsr getTileFlags
+	and #4			; blocker sprite?
+	bne .hitEdge		; if yes, stop tracing here
+	jmp .spriteDone		; if not, keep tracing
+.notDone:
 	; Haven't seen this one yet. Mark it, and also record the address of the flag
 	; so we can clear it later after tracing all rays.
 	lda (pMap),y		; get back the original byte
@@ -434,11 +436,10 @@ castRay: !zone
 	jsr drawSprite		; put it on screen
 +	pla
 	tay			; restore map position index
-!if BLOCKER_FOO {
-	lda txNum
-	cmp #1
-	beq .hitEdge
-}
+	ldx txNum
+	jsr getTileFlags
+	and #4			; blocker sprite?
+	bne .hitEdge		; if yes, stop tracing rays
 .spriteDone:
 	jmp .DDA_step		; trace this ray some more
 
@@ -1553,6 +1554,12 @@ setPlayerPos: !zone
 	sta playerDir
 	rts
 
+;-------------------------------------------------------------------------------
+getTileFlags: !zone
+	dex			; because tile numbers start at 1 but list at 0
+	lda $1111,x
+	rts
+
 ;-------------------------------------------------------------------------------
 ; Load the texture expansion code, copy it to aux mem
 loadTextures: !zone
@@ -1607,7 +1614,15 @@ loadTextures: !zone
 	brk		; barf out if too many textures
 +	stx txNum
 	jmp .lup
-.done:	; end of the texture numbers is the base of the map data - record it
+.done:	; end of texture numbers is the list of tile flags
+	lda .get+1
+	sta getTileFlags+2
+	lda .get+2
+	sta getTileFlags+3
+-	jsr .get	; skip over the flags now
+	tay
+	bne -
+	; end of the texture flags is the base of the map data - record it
 	lda .get+1
 	sta mapBase
 	lda .get+2
@@ -1668,13 +1683,18 @@ calcMapOrigin: !zone
 
 ;-------------------------------------------------------------------------------
 ; Retrieve the map data where the player currently is
-getMapCell: !zone
+isBlocked: !zone
 	jsr calcMapOrigin
 	sta pMap
 	sty pMap+1
 	ldy playerX+1
 	lda (pMap),y
-	rts
+	beq +
+	and #$3F
+	tax
+	jsr getTileFlags
+	and #2			; flag 2 is for obstructions
++	rts
 
 ;-------------------------------------------------------------------------------
 ; Cast all the rays from the current player coord