diff --git a/res/CACHE00.IDX b/res/CACHE00.IDX
index 3dd31d61..017a7a83 100644
Binary files a/res/CACHE00.IDX and b/res/CACHE00.IDX differ
diff --git a/res/CACHE01.IDX b/res/CACHE01.IDX
index 005d4f04..7a27bebd 100644
Binary files a/res/CACHE01.IDX and b/res/CACHE01.IDX differ
diff --git a/res/CACHE10.IDX b/res/CACHE10.IDX
index 6acb7dfe..a3af5b47 100644
Binary files a/res/CACHE10.IDX and b/res/CACHE10.IDX differ
diff --git a/res/CACHE11.IDX b/res/CACHE11.IDX
index a4516f91..c5fa8448 100644
Binary files a/res/CACHE11.IDX and b/res/CACHE11.IDX differ
diff --git a/res/GAMEHELP/THE.HUMAN.FLY b/res/GAMEHELP/THE.HUMAN.FLY
new file mode 100644
index 00000000..bb83c164
--- /dev/null
+++ b/res/GAMEHELP/THE.HUMAN.FLY
@@ -0,0 +1,16 @@
+
+           Climb the building
+
+             Avoid obstacles
+
+
+             W - left hand
+
+             U - left hand
+
+            <- A then space
+
+            -> L then space
+
+     Press space during earthquakes
+[eof]
diff --git a/res/GAMES.CONF b/res/GAMES.CONF
index dcc7bd4b..486e2e86 100755
--- a/res/GAMES.CONF
+++ b/res/GAMES.CONF
@@ -191,6 +191,7 @@
 00011,GALAXY.GATES=Galaxy Gates
 10011,GAMMA.GOBLINS=Gamma Goblins
 01010,GAUNTLET=Gauntlet
+00010,GEMINI=Gemini
 10011,GENESIS=Genesis
 00011,GENETIC.DRIFT=Genetic Drift
 00010,GENIUS=Genius
@@ -443,6 +444,7 @@
 01110,TS=The Chase on Tom S's Island
 10010,THE.GOONIES=The Goonies
 00070,THE.HEIST=The Heist
+00011,THE.HUMAN.FLY=The Human Fly
 10010,LG=The Last Gladiator
 11110,THE.LAST.NINJA=The Last Ninja
 11060,MM=The Movie Monster Game
diff --git a/res/TITLE.HGR.UNPACKED/GEMINI b/res/TITLE.HGR.UNPACKED/GEMINI
new file mode 100644
index 00000000..5a0ab468
Binary files /dev/null and b/res/TITLE.HGR.UNPACKED/GEMINI differ
diff --git a/res/TITLE.HGR.UNPACKED/THE.HUMAN.FLY b/res/TITLE.HGR.UNPACKED/THE.HUMAN.FLY
new file mode 100644
index 00000000..3a174003
Binary files /dev/null and b/res/TITLE.HGR.UNPACKED/THE.HUMAN.FLY differ
diff --git a/res/TITLE.HGR/GEMINI b/res/TITLE.HGR/GEMINI
new file mode 100644
index 00000000..b1a668b3
Binary files /dev/null and b/res/TITLE.HGR/GEMINI differ
diff --git a/res/TITLE.HGR/THE.HUMAN.FLY b/res/TITLE.HGR/THE.HUMAN.FLY
new file mode 100644
index 00000000..c738ae02
Binary files /dev/null and b/res/TITLE.HGR/THE.HUMAN.FLY differ
diff --git a/res/dsk/gemini 7k file PRODOS (san inc pack).po b/res/dsk/gemini 7k file PRODOS (san inc pack).po
new file mode 100644
index 00000000..fca6a6e1
Binary files /dev/null and b/res/dsk/gemini 7k file PRODOS (san inc pack).po differ
diff --git a/res/dsk/the human fly 15k file PRODOS (san inc pack).po b/res/dsk/the human fly 15k file PRODOS (san inc pack).po
new file mode 100644
index 00000000..de7e10f7
Binary files /dev/null and b/res/dsk/the human fly 15k file PRODOS (san inc pack).po differ
diff --git a/src/index/artwork.idx.a b/src/index/artwork.idx.a
index 4c81185c..8acfe2eb 100644
--- a/src/index/artwork.idx.a
+++ b/src/index/artwork.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15178679
+         !be24  15194282
          !le16     5108
diff --git a/src/index/attract.idx.a b/src/index/attract.idx.a
index cf1d8fe7..7c00b1d8 100644
--- a/src/index/attract.idx.a
+++ b/src/index/attract.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15125463
+         !be24  15141000
          !le16     5605
diff --git a/src/index/cache00.idx.a b/src/index/cache00.idx.a
index 24a2cfec..6b4649af 100644
--- a/src/index/cache00.idx.a
+++ b/src/index/cache00.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15060256
-         !le16     3993
+         !be24  15075498
+         !le16     4012
diff --git a/src/index/cache01.idx.a b/src/index/cache01.idx.a
index 02ba1e0e..18528a11 100644
--- a/src/index/cache01.idx.a
+++ b/src/index/cache01.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15074324
-         !le16     4412
+         !be24  15089647
+         !le16     4431
diff --git a/src/index/cache10.idx.a b/src/index/cache10.idx.a
index e92121ae..ac728062 100644
--- a/src/index/cache10.idx.a
+++ b/src/index/cache10.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15091946
-         !le16     5632
+         !be24  15107350
+         !le16     5651
diff --git a/src/index/cache11.idx.a b/src/index/cache11.idx.a
index 0e68ce27..2c35f117 100644
--- a/src/index/cache11.idx.a
+++ b/src/index/cache11.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15112111
-         !le16     6248
+         !be24  15127596
+         !le16     6267
diff --git a/src/index/count00.a b/src/index/count00.a
index 5fe49261..f729cc01 100644
--- a/src/index/count00.a
+++ b/src/index/count00.a
@@ -3,4 +3,4 @@
 ;
 ; This file is automatically generated
 ;
-!word      301
+!word      303
diff --git a/src/index/count01.a b/src/index/count01.a
index 42a97f1e..de38bac8 100644
--- a/src/index/count01.a
+++ b/src/index/count01.a
@@ -3,4 +3,4 @@
 ;
 ; This file is automatically generated
 ;
-!word      328
+!word      330
diff --git a/src/index/count10.a b/src/index/count10.a
index 1755f8bd..fc838390 100644
--- a/src/index/count10.a
+++ b/src/index/count10.a
@@ -3,4 +3,4 @@
 ;
 ; This file is automatically generated
 ;
-!word      426
+!word      428
diff --git a/src/index/count11.a b/src/index/count11.a
index a6208c98..32d9bcf5 100644
--- a/src/index/count11.a
+++ b/src/index/count11.a
@@ -3,4 +3,4 @@
 ;
 ; This file is automatically generated
 ;
-!word      468
+!word      470
diff --git a/src/index/coverfade.idx.a b/src/index/coverfade.idx.a
index 63ff053c..7ff4062c 100644
--- a/src/index/coverfade.idx.a
+++ b/src/index/coverfade.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15183787
+         !be24  15199390
          !le16      410
diff --git a/src/index/credits.idx.a b/src/index/credits.idx.a
index 68bc1505..83635e3b 100644
--- a/src/index/credits.idx.a
+++ b/src/index/credits.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15184541
+         !be24  15200144
          !le16      448
diff --git a/src/index/decrunch.idx.a b/src/index/decrunch.idx.a
index 8b184b76..a6f55871 100644
--- a/src/index/decrunch.idx.a
+++ b/src/index/decrunch.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15184989
+         !be24  15200592
          !le16      303
diff --git a/src/index/demo.idx.a b/src/index/demo.idx.a
index 9565eb87..031a71ef 100644
--- a/src/index/demo.idx.a
+++ b/src/index/demo.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  12123530
-         !le16     1652
+         !be24  12138890
+         !le16     2112
diff --git a/src/index/dfx.idx.a b/src/index/dfx.idx.a
index c7ab43a6..02897516 100644
--- a/src/index/dfx.idx.a
+++ b/src/index/dfx.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15133708
+         !be24  15149245
          !le16     1640
diff --git a/src/index/dgr.fizzle.idx.a b/src/index/dgr.fizzle.idx.a
index c3e478d8..4af1db66 100644
--- a/src/index/dgr.fizzle.idx.a
+++ b/src/index/dgr.fizzle.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15184273
+         !be24  15199876
          !le16       67
diff --git a/src/index/dgr.idx.a b/src/index/dgr.idx.a
index 7c843b2c..49e508fa 100644
--- a/src/index/dgr.idx.a
+++ b/src/index/dgr.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15178620
+         !be24  15194223
          !le16       59
diff --git a/src/index/dhgr.idx.a b/src/index/dhgr.idx.a
index 305be4a8..644edd0f 100644
--- a/src/index/dhgr.idx.a
+++ b/src/index/dhgr.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15177086
+         !be24  15192689
          !le16     1437
diff --git a/src/index/dtitle.idx.a b/src/index/dtitle.idx.a
index 37ff78d9..e729007a 100644
--- a/src/index/dtitle.idx.a
+++ b/src/index/dtitle.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15161836
+         !be24  15177439
          !le16      537
diff --git a/src/index/fx.idx.a b/src/index/fx.idx.a
index 7164f7b8..1b12218b 100644
--- a/src/index/fx.idx.a
+++ b/src/index/fx.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15131068
+         !be24  15146605
          !le16     2640
diff --git a/src/index/gamehelp.idx.a b/src/index/gamehelp.idx.a
index 55ede819..29c11c9f 100644
--- a/src/index/gamehelp.idx.a
+++ b/src/index/gamehelp.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15135706
-         !le16     7104
+         !be24  15151243
+         !le16     7137
diff --git a/src/index/gr.fizzle.idx.a b/src/index/gr.fizzle.idx.a
index b40740ee..a432b75b 100644
--- a/src/index/gr.fizzle.idx.a
+++ b/src/index/gr.fizzle.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15184197
+         !be24  15199800
          !le16       76
diff --git a/src/index/gr.idx.a b/src/index/gr.idx.a
index 9f69600a..dc26fd17 100644
--- a/src/index/gr.idx.a
+++ b/src/index/gr.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15178523
+         !be24  15194126
          !le16       97
diff --git a/src/index/helptext.idx.a b/src/index/helptext.idx.a
index 38a057e1..dd525f40 100644
--- a/src/index/helptext.idx.a
+++ b/src/index/helptext.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15184340
+         !be24  15199943
          !le16      201
diff --git a/src/index/hgr0.idx.a b/src/index/hgr0.idx.a
index ef2463e0..c0614e3e 100644
--- a/src/index/hgr0.idx.a
+++ b/src/index/hgr0.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15162373
+         !be24  15177976
          !le16     4702
diff --git a/src/index/hgr1.idx.a b/src/index/hgr1.idx.a
index 2a76ca3d..cf2ca91c 100644
--- a/src/index/hgr1.idx.a
+++ b/src/index/hgr1.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15167075
+         !be24  15182678
          !le16     1702
diff --git a/src/index/hgr2.idx.a b/src/index/hgr2.idx.a
index 9bcdee83..34646452 100644
--- a/src/index/hgr2.idx.a
+++ b/src/index/hgr2.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15168777
+         !be24  15184380
          !le16     1129
diff --git a/src/index/hgr3.idx.a b/src/index/hgr3.idx.a
index 96663266..a6cc0ee3 100644
--- a/src/index/hgr3.idx.a
+++ b/src/index/hgr3.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15169906
+         !be24  15185509
          !le16     3388
diff --git a/src/index/hgr4.idx.a b/src/index/hgr4.idx.a
index cce49448..97cf73d0 100644
--- a/src/index/hgr4.idx.a
+++ b/src/index/hgr4.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15173294
+         !be24  15188897
          !le16     3199
diff --git a/src/index/hgr5.idx.a b/src/index/hgr5.idx.a
index e1b948d4..35a8dbaa 100644
--- a/src/index/hgr5.idx.a
+++ b/src/index/hgr5.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15176493
+         !be24  15192096
          !le16      479
diff --git a/src/index/hgr6.idx.a b/src/index/hgr6.idx.a
index 8e8fc535..569ed4c9 100644
--- a/src/index/hgr6.idx.a
+++ b/src/index/hgr6.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15176972
+         !be24  15192575
          !le16      114
diff --git a/src/index/joystick.idx.a b/src/index/joystick.idx.a
index f7dca57e..be22fa87 100644
--- a/src/index/joystick.idx.a
+++ b/src/index/joystick.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15185292
+         !be24  15200895
          !le16     2370
diff --git a/src/index/miniattract0.idx.a b/src/index/miniattract0.idx.a
index 982838a8..41e43e78 100644
--- a/src/index/miniattract0.idx.a
+++ b/src/index/miniattract0.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15148079
+         !be24  15163649
          !le16     4728
diff --git a/src/index/miniattract1.idx.a b/src/index/miniattract1.idx.a
index 74ff8a28..fe74e0a9 100644
--- a/src/index/miniattract1.idx.a
+++ b/src/index/miniattract1.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15152807
+         !be24  15168377
          !le16     2380
diff --git a/src/index/prelaunch.idx.a b/src/index/prelaunch.idx.a
index 36727db7..425e8d56 100644
--- a/src/index/prelaunch.idx.a
+++ b/src/index/prelaunch.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15118359
-         !le16     7104
+         !be24  15133863
+         !le16     7137
diff --git a/src/index/res.cover.idx.a b/src/index/res.cover.idx.a
index 27596c0e..97b2ceec 100644
--- a/src/index/res.cover.idx.a
+++ b/src/index/res.cover.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  4016640
+         !be24  4032000
          !le16     8192
diff --git a/src/index/res.help.idx.a b/src/index/res.help.idx.a
index 9f2b0c94..96c27414 100644
--- a/src/index/res.help.idx.a
+++ b/src/index/res.help.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  4033024
+         !be24  4048384
          !le16     8192
diff --git a/src/index/res.title.idx.a b/src/index/res.title.idx.a
index ca509a26..07fa286a 100644
--- a/src/index/res.title.idx.a
+++ b/src/index/res.title.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  4024832
+         !be24  4040192
          !le16     8192
diff --git a/src/index/search00.idx.a b/src/index/search00.idx.a
index 994091d0..a0203a1a 100644
--- a/src/index/search00.idx.a
+++ b/src/index/search00.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15051055
-         !le16     9201
+         !be24  15066235
+         !le16     9263
diff --git a/src/index/search01.idx.a b/src/index/search01.idx.a
index 39146302..e9a4a3cb 100644
--- a/src/index/search01.idx.a
+++ b/src/index/search01.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15064249
-         !le16    10075
+         !be24  15079510
+         !le16    10137
diff --git a/src/index/search10.idx.a b/src/index/search10.idx.a
index 411a2c2a..ddfbd539 100644
--- a/src/index/search10.idx.a
+++ b/src/index/search10.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15078736
-         !le16    13210
+         !be24  15094078
+         !le16    13272
diff --git a/src/index/search11.idx.a b/src/index/search11.idx.a
index 850ab77b..68a671dd 100644
--- a/src/index/search11.idx.a
+++ b/src/index/search11.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15097578
-         !le16    14533
+         !be24  15113001
+         !le16    14595
diff --git a/src/index/sfx.idx.a b/src/index/sfx.idx.a
index 0235145b..db50b3d3 100644
--- a/src/index/sfx.idx.a
+++ b/src/index/sfx.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15135348
+         !be24  15150885
          !le16      358
diff --git a/src/index/slideshow.idx.a b/src/index/slideshow.idx.a
index 44802dee..9f0f6749 100644
--- a/src/index/slideshow.idx.a
+++ b/src/index/slideshow.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15142810
+         !be24  15158380
          !le16     5269
diff --git a/src/index/title.idx.a b/src/index/title.idx.a
index f74d3eeb..fd559d04 100644
--- a/src/index/title.idx.a
+++ b/src/index/title.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15155187
-         !le16     6649
+         !be24  15170757
+         !le16     6682
diff --git a/src/index/xsingle.idx.a b/src/index/xsingle.idx.a
index be3f65c3..839e22f9 100644
--- a/src/index/xsingle.idx.a
+++ b/src/index/xsingle.idx.a
@@ -4,5 +4,5 @@
 ; This file is automatically generated
 ;
          !byte 0
-         !be24  15047072
-         !le16     3983
+         !be24  15062249
+         !le16     3986
diff --git a/src/prelaunch/gemini.a b/src/prelaunch/gemini.a
new file mode 100644
index 00000000..96d4538a
--- /dev/null
+++ b/src/prelaunch/gemini.a
@@ -0,0 +1,27 @@
+;license:MIT
+;(c) 2022 by qkumba
+
+!cpu 6502
+!to "build/PRELAUNCH.INDEXED/GEMINI",plain
+*=$106
+
+    !source "src/prelaunch/common.a"
+
+         +ENABLE_ACCEL
+         lda   #$60
+         sta   $7E2A
+         jsr   $6200       ; decompress
+         +READ_RAM2_NO_WRITE
+         lda   MachineStatus
+         and   #CHEATS_ENABLED
+         beq   +
+         lda   #$ad
+         sta   $D0C        ; patch - don't decrease lives
++
+         jsr   DisableAccelerator
+         +READ_ROM_NO_WRITE
+         jmp   $D566
+
+!if * > $1C0 {
+  !error "code is too large, ends at ", *
+}
diff --git a/src/prelaunch/the.human.fly.a b/src/prelaunch/the.human.fly.a
new file mode 100644
index 00000000..7e8eb1ef
--- /dev/null
+++ b/src/prelaunch/the.human.fly.a
@@ -0,0 +1,42 @@
+;license:MIT
+;(c) 2022 by qkumba
+
+!cpu 6502
+!to "build/PRELAUNCH.INDEXED/THE.HUMAN.FLY",plain
+*=$106
+
+    !source "src/prelaunch/common.a"
+
+         +ENABLE_ACCEL
+         lda   #$60
+         sta   $8759
+         sta   $8770
+         jsr   $4B00       ; decompress
+         lda   #(callback / 100) + 48
+         sta   $87D
+         lda   #((callback % 100) / 10) + 48
+         sta   $87E
+         lda   #(callback % 10) + 48
+         sta   $87F
+         lda   #0
+         sta   $880
+         +DISABLE_ACCEL
+         jmp   $D566
+
+callback
+         +ENABLE_ACCEL
+         jsr   $875C       ; decompress more
+         +READ_RAM2_NO_WRITE
+         lda   MachineStatus
+         and   #CHEATS_ENABLED
+         beq   +
+         lda   #$2c
+         sta   $4D24       ; patch - don't decrease lives
++
+         jsr   DisableAccelerator
+         +READ_ROM_NO_WRITE
+         jmp   $1100
+
+!if * > $1C0 {
+  !error "code is too large, ends at ", *
+}
diff --git a/winmake.bat b/winmake.bat
index 8cb75c7a..aa07f014 100644
--- a/winmake.bat
+++ b/winmake.bat
@@ -52,11 +52,10 @@ echo|set/p="adding files..."
 %CADIUS% ADDFILE "build\%DISK%" "/%VOLUME%/" "build\TOTAL.DATA" -C >>build\log
 if "%2". equ "". (
   for %%q in (build\PREFS.CONF res\Finder.Data res\Finder.Root) do %CADIUS% ADDFILE "build\%DISK%" "/%VOLUME%/" "build\%%~nxq" -C >>build\log
-  for %%q in (res\DEMO res\TITLE.ANIMATED res\ICONS build\FX build\PRELAUNCH) do (
+  for %%q in (res\TITLE.ANIMATED res\ICONS build\FX build\PRELAUNCH) do (
     1>nul 2>nul del /s "%%q\.DS_Store"
     %CADIUS% ADDFOLDER "build\%DISK%" "/%VOLUME%/%%~nxq" %%q -C >>build\log
   )
-  for %%q in (1 2 3 4 5 6) do %CADIUS% RENAMEFILE "build\%DISK%" "/%VOLUME%/DEMO/SPCARTOON.%%q%%q" "SPCARTOON.%%q." >>build\log
   %CADIUS% CREATEFOLDER "build\%DISK%" "/%VOLUME%/X/" -C >>build\log
   %CADIUS% ADDFOLDER "build\%DISK%" "/%VOLUME%/X" "build\X" -C >>build\log
   cscript /nologo bin\changebootloader.js "build\%DISK%" build\proboothd
@@ -95,6 +94,7 @@ goto :EOF
 call :md
 call :asmfx
 call :asmprelaunch
+call :asmdemo
 rem
 rem precompute binary data structure for mega-attract mode configuration file
 rem
@@ -220,6 +220,14 @@ echo|set/p="indexing shr..."
 cscript /nologo bin\buildss.js res\ARTWORK.SHR build\ARTWORK.IDX nul build\TOTAL.DATA nul >>build\log
 echo done
 rem
+rem precompute indexed files for demo launchers
+rem note: these can not be padded because some of them are loaded too close to $C000
+rem
+echo|set/p="indexing demos..."
+cscript /nologo bin\buildss.js build\DEMO build\DEMO.IDX nul build\TOTAL.DATA nul >>build\log
+cscript /nologo bin\addfile.js build\DEMO.IDX src\index\demo.idx.a
+echo done
+rem
 rem precompute indexed files for single-load game binaries
 rem note: these can be padded because they are loaded at a time when all of main memory is clobber-able
 rem
@@ -300,6 +308,7 @@ goto :EOF
 2>nul md build\ATTRACT1
 2>nul md build\SS
 2>nul md build\GAMEHELP
+2>nul md build\DEMO
 1>nul copy nul build\log
 goto :EOF
 
@@ -312,6 +321,16 @@ for /f "tokens=*" %%q in (build\relbase.log) do set _make=%%q
 %ACME% -DBUILDNUMBER=%_build% -DRELBASE=$!_make:~-5,4! -r build\4cade.lst src\4cade.a
 goto :EOF
 
+:asmdemo
+echo|set/p="building demos..."
+for %%q in (src\demo\*.a) do (
+  for /f "tokens=* usebackq" %%k in (`find "^!to" %%q`) do set _to=%%k
+  set _to=!_to:~0,1!
+  if !_to!==t %ACME% %%q
+)
+echo done
+goto :EOF
+
 :asmfx
 echo|set/p="building fx..."
 for %%q in (src\fx\*.a) do (