diff --git a/artwork/shapes.asm b/artwork/shapes.asm
index b5542f8..cccdfc1 100644
--- a/artwork/shapes.asm
+++ b/artwork/shapes.asm
@@ -80,7 +80,7 @@ ShapesTableH
     .by >bird_2
     .by >cactus_0
 diff_object_gap ; min distance between obstacles by difficulty level
-    :16 .by 20-#
+    :DIFF_LEVELS .by 20-#
 ;----------vars----------
 diff_level  .ds 1
 
diff --git a/dino.asm b/dino.asm
index a8bc12f..a54b2d8 100644
--- a/dino.asm
+++ b/dino.asm
@@ -212,6 +212,9 @@ Shift
     bne @-
     ;all zeroes
 insertObject
+    lda RANDOM
+    and #%00000001  ; insert 50/50
+    beq noInsert
     mva #1 WorldTable+WORLD_LENGTH-2
     inc diff_level
     
diff --git a/intro/difficulties.bmp b/intro/difficulties.bmp
new file mode 100644
index 0000000..35ccf90
Binary files /dev/null and b/intro/difficulties.bmp differ
diff --git a/intro/difficulties.png b/intro/difficulties.png
new file mode 100644
index 0000000..6371fd8
Binary files /dev/null and b/intro/difficulties.png differ
diff --git a/intro/difficulties.xcf b/intro/difficulties.xcf
new file mode 100644
index 0000000..3723816
Binary files /dev/null and b/intro/difficulties.xcf differ
diff --git a/intro/please_wait.wav b/intro/please_wait.wav
new file mode 100644
index 0000000..580c4b3
Binary files /dev/null and b/intro/please_wait.wav differ
diff --git a/intro/tech_diff.asm b/intro/tech_diff.asm
new file mode 100644
index 0000000..7887e55
--- /dev/null
+++ b/intro/tech_diff.asm
@@ -0,0 +1,45 @@
+; tech diff https://www.youtube.com/live/xXDjtDJf69E?si=Sg9HLaZ1krfz-m12&t=1578
+;---------------------------------------------------
+    OPT r+
+
+;---------------------------------------------------
+; Zpage variables
+    .zpvar temp_w   .word = $80
+    .zpvar temp_b   .byte
+;---------------------------------------------------
+    icl '../lib/ATARISYS.ASM'
+    icl '../lib/MACRO.ASM'
+;---------------------------------------------------
+    ; dark screean and BASIC off
+    ORG $2000
+    mva #0 dmactls             ; dark screen
+    mva #$ff portb
+    ; and wait one frame :)
+    seq:wait                   ; or waitRTC ?
+    mva #$ff portb        ; BASIC off
+    rts
+    ini $2000
+;---------------------------------------------------
+
+    org $2000
+screen
+    ins 'difficulties.bmp',+146
+DL
+    :13 .by SKIP8
+    .by MODEF+LMS
+    .wo screen
+    :25 .by MODEF
+    .by JVB
+    .wo DL
+    
+start
+    mwa #DL dlptrs
+    lda #%00111110  ; normal screen width, DL on, P/M on
+    sta dmactls
+    mva #0 COLOR2
+    sta COLBAK
+    mva #15 COLOR1
+    halt
+
+    ini start
+    
\ No newline at end of file
diff --git a/intro/technical_difficulties.png b/intro/technical_difficulties.png
new file mode 100644
index 0000000..f7938d7
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