diff --git a/dino.asm b/dino.asm
index 504c958..5407814 100644
--- a/dino.asm
+++ b/dino.asm
@@ -1,5 +1,5 @@
 SCR_HEIGHT = 8
-WORLD_LENGTH = 64
+WORLD_LENGTH = 48
 DIFF_LEVELS = 20
 .IFNDEF ALONE
     .def ALONE = 1 ; standalone version
@@ -25,6 +25,7 @@ swap_table=$0600    ; table for swap bytes in left characters :)
     .zpvar Hit              .byte
     .zpvar Level            .byte
     .zpvar play_flag        .byte
+    .zpvar NTSCounter       .byte
 ;---------------------------------------------------
     icl 'lib/ATARISYS.ASM'
     icl 'lib/MACRO.ASM'
@@ -72,12 +73,12 @@ status_line_addr
     :4 .byte SKIP8
     .byte MODE2
 
-    .byte SKIP8,SKIP8 ; empty lines
+    .byte SKIP8,SKIP8,SKIP8 ; empty lines
 
-    .rept SCR_HEIGHT, #
+    .rept SCR_HEIGHT-1, #
       .byte MODE2+LMS+SCH   ; gr.0+LMS+HSCRL
 line:1_addr
-        .word screen+$100*#
+        .word screen+$100*(#+1)
     .endr
     .byte JVB   
     .word GameDL
@@ -400,18 +401,19 @@ SwapLoop
     bpl @-
     rts
 .endp
+;-----------------------------------------------
 .proc ClearScreen
     ldy #44 ; visible screen len
     lda #0
 ClearLoop
-    sta screen+$0700,y
+    ;sta screen+$0700,y
     sta screen+$0600,y
     sta screen+$0500,y
     sta screen+$0400,y
     sta screen+$0300,y
     sta screen+$0200,y
     sta screen+$0100,y
-    sta screen+$0000,y
+    ;sta screen+$0000,y
     dey
     bne ClearLoop
     rts
@@ -1324,6 +1326,7 @@ pressed
 .proc PrepareMusicPlayer
     jsr StopMusic
     VMAIN VBLinterrupt,7       ; jsr SetVBL
+    mva #0 NTSCounter
     rts
 .endp
 .proc PlayInGameMusic
@@ -1348,9 +1351,23 @@ pressed
 .endp
 .proc VBLinterrupt
     lda play_flag
-    beq @+
+    beq NoMusic
+    ; music - PAL/NTSC check
+    lda PAL
+    and #%00001110
+    beq IsPAL
+    ; NTSC ...
+    inc NTSCounter
+    lda NTSCounter
+    cmp #5
+    bne PlayMusic
+    mva #0 NTSCounter
+    beq NoMusic
+PlayMusic
+IsPAL    
     jsr PLAYER
-@   pla
+NoMusic
+    pla
     tay
     pla
     tax
diff --git a/dino.xex b/dino.xex
index 009f354..eed0032 100644
Binary files a/dino.xex and b/dino.xex differ
diff --git a/intro/tech_diff.asm b/intro/tech_diff.asm
index ae0e9fd..e1e5095 100644
--- a/intro/tech_diff.asm
+++ b/intro/tech_diff.asm
@@ -8,6 +8,7 @@
     .zpvar temp_b   .byte
     .zpvar temp_w2  .word
     .zpvar temp_w3  .word
+    .zpvar NTSCounter    .byte
 ;---------------------------------------------------
     icl '../lib/ATARISYS.ASM'
     icl '../lib/MACRO.ASM'
@@ -86,6 +87,9 @@ next_letter
 leet_end
     jsr StopMusic
     jsr wait_for_releasing_keyz
+        mva #0 dmactls      ; dark screen
+        ; and wait one frame :)
+        waitRTC
     rts
     
 
@@ -152,6 +156,7 @@ leet_speeks_h
     mwa #MUSIC_DATA_END song_end_ptr
     jsr init_song
     VMAIN VBLinterrupt,7       ; jsr SetVBL
+    mva #0 NTSCounter
     rts
 .endp
 .proc StopMusic
@@ -166,7 +171,21 @@ leet_speeks_h
     rts
 .endp
 .proc VBLinterrupt
+    ; music - PAL/NTSC check
+    lda PAL
+    and #%00001110
+    beq IsPAL
+    ; NTSC ...
+    inc NTSCounter
+    lda NTSCounter
+    cmp #5
+    bne PlayMusic
+    mva #0 NTSCounter
+    beq NoMusic
+PlayMusic
+IsPAL    
     jsr PLAYER
+NoMusic
     jmp XITVBV
 .endp  
 leet_screen 
diff --git a/intro/tech_diff.xex b/intro/tech_diff.xex
index 9def452..d0c2aa2 100644
Binary files a/intro/tech_diff.xex and b/intro/tech_diff.xex differ
diff --git a/tdc.xex b/tdc.xex
index c4335e7..53f4ce2 100644
Binary files a/tdc.xex and b/tdc.xex differ