FOR ANYONE INTERESTED, check out the amount of gamecode changes for the LE. Its the same for the PRO, or similar anyway.

V1.5 - April 27, 2012
=====================

  - Removed the definitions for the lower playfield end-of-stroke switches,
    as these have been removed and were never in any of the production games.
    So now they will no longer be reported in Tech Alert.
  - The upper playfield flippers were not being turned off during "Hells
    Bells" and "Highway To Hell" when the ball was held and the lower
    playfield was being played.  This has been corrected.
  - If the ball leaves a device while the lower playfield is being played,
    the upper playfield flippers will be turned back on.
  - More time was added to settle the bell eject after a kick.
  - Playfield multiplier now paused when the lower playfield is active.
  - Added backgrounds for "Hells Bells" and "Highway To Hell" lower playfield.
  - 2X, 3X, and jukebox song title lamp states are now displayed when the
    lower playfield is active.
  - Removed lamp effects that manipulated the G.I. relay.
  - Ball search for the bell magnet was not ignoring the bell opto switch
    and keeping it from scoring a hit on the bell.  This has been corrected.
  - Fixed a resource conflict with the song select G.I. backgrounds.  These
    now work as intended.

  - Completing all of the white note arrow shots during a song now adds 2.5M
    to the song jackpot.  This can be done any number of times.
  - Timers are now paused when the player is choosing a song.  (This fixes the
    issue of the ball saver timing down at the start of a new ball when the
    player plunges the ball into the jukebox and takes some time picking a new
    song.)
  - Added artwork for the start of "Hells Bells".
  - Added a sound for tilt.
  - All white note arrow shots completed during a song records 3 units of
    permanent progress (one time, adjustable), such that completing notes
    and changing songs will continually lock in higher scores for new songs.
  - Super loops no longer has any effect on whether the right control gate
    causes the ball to loop around, so if "Whole Lotta Rosie" or "You Shook
    Me All Night Long" are running, the ball will go into the pop bumpers.
  - Added jackpot information to the super loops award display effect.
  - Added sounds for "Let There Be Rock".
  - Cannon targets are now displayed in order of increasing score.
  - Added song jackpot to tour multiball.
  - Changed the lamp effect for a spinner hit during "War Machine".
  - Added a sound for the War Machine bay doors opening.
  - Lowered spinner scores.
  - Changed bell target hit artwork.  The new art includes the AC/DC logo on
    the bell.
  - Fixed an issue with transitioning from the shooter groove music to the
    main play music.  The main play music would cut off the very beginning
    of the shooter groove music if the ball was on the playfield during
    the first bar of the shooter groove music.
  - Added the car dip animation to the bumper hits for "You Shook Me All
    Night Long".  This fixes the bad rendering of the girls over the car on
    frames #3, #4, and #5.
  - Added a sound for hitting the T.N.T. targets during T.N.T.
  - Added more information to song collect display effects when the song is
    selected.
  - Fixed mode start text (vertical centering, it was off by 1 pixel).
  - Added T.N.T. start dots.
  - Cleaned up cannon lamp effects.
  - Added art to the "Bump 'N' Win" award display effect.
  - Added an animation for the start of "You Shook Me All Night Long".
  - Fixed up some mode key sounds.
  - Lowered the left ramp score during Rock N Roll Train.
  - Changed bonus.  The current formula is:
    (25K * number of songs lit
     +
     50K * number of songs played, +50K more if all white note shots for the
     song were completed)
    *
    bonus multiplier
    *
    (3 if triple bonus, 2 if double bonus).
  - Added sounds for skill shot, super skill shot, and highway to hell start.
  - Added art for "Let There Be Rock".

V1.4 - March 22, 2012
=====================

  - Thunderstruck and hells bells music loop did not loop properly.
    This has been corrected.
  - Added instant info for jam multiball.
  - Added instant info for tour multiball.
  - Cleaned up tour multiball.  Tour names are now displayed, along with
    a variety of ticket stubs.
  - Added to instant info for album multiball.
  - Added display effects for completing tour multiball and jam multiball.
  - Increased the scores for the T.N.T. mode.
  - Changed default ramp shots to re-light the jam multiball super jackpot
    from 4 to 6.
  - Added highway to hell start art.
  - Added tour/jam/album multiball super jackpots.
  - Changed target multiball super jackpot re-light to completing a number
    of target banks instead of completing all target banks.
  - Fixed a problem with firing the flasher for the multiball super
    jackpot(s) on the cannon->bell.
  - Fixed song bonuses for album multiball and tour multiball.  These were
    not awarding the first 1M as they should have been.
  - Added bell flasher to multiball super jackpot cannon shot.
  - Changed mode collect scoring.  If the song is NOT changed, the bonus
    is: (50K * # of songs lit) + an additional (200K) if all 11 songs have
   been lit.  If the song IS changed, the bonus is (500K * # of songs
   completed) + (50K * # of songs lit) + an additional 200K if all songs
   that have not been completed have been lit.
  - Fixed audit names so they fit on the display.
  - Added loop jackpot, combo jackpot, and target jackpot to the cannon
    awards.
  - Changed the priorities of the mode pop bumper award display effects so
    they would not cut off the top lane display effects.
  - Lowered train combo score.
  - Added title messages to skill shot and super skill shot.
  - Fixed skill shot "items" text error.
  - Cannon mode was not being marked solid properly.  This has been
    corrected.
  - Removed the cannon mode lock via the fire button and the randomizing
    of the cannon modes.  The sequence is always: FODDER, VOLLEY, CHAOS.
  - Super modes are now only randomized on the ramp standup targets.
  - Added animating people to the cannon sequence display effects.
  - Added art for red arrow shots.
  - Fixed a problem with the cannon flasher not flashing when multiball
    was ready.
  - Cleaned up cannon artwork.
  - Added cannon speech.
  - Fixed problems in "Hell Ain't A Bad Place To Be", "Hells Bells", and
    "Highway To Hell", where hitting the main shot for the rule would not
   re-light the white arrow shots.
  - Added sounds for extra ball and special.
  - Added song jackpot HSTD.
  - Added the song jackpot score to the song select background display
    effect.
  - Song jackpot now carries over from song to song.
  - Fixed several issues with the cannon and "For Those About To Rock".
  - Added artwork and a display effect for replay.
  - Added artwork for highway to hell, for those about to rock, and extra
    ball.
  - Fixed mode setup such that the song for every player in competition
    mode will not be "Back In Black".
  - Redesigned cannon handling so all game features that want to use the
    cannon can co-exist peacefully.
  - All songs now award add-a-ball when white arrow note shots are
    completed during multiball.
  - Added more unique combos.
  - Changed highway to hell art.
  - Changed some thunderstruck sounds.
  - Lowered Rosie lane scores.
  - Added riffs for multiballs.
  - Added sounds to bonus count.
  - Added top eject kick sound and a lamp effect.
  - Changed the sound for completing the top lanes.
  - Added sounds for top lanes.
  - Added a bonus for selecting a song (be it the same song or a new one).
  - Cleaned up "Let There Be Rock" and "Hell Ain't A Bad Place To Be"
    modes.
  - Cleaned up "Highway To Hell" and "Hells Bells" modes.
  - Fixed an issue with the TNT background showing some dynamite in a
    bright color when it should have been dim.
  - Changed project to use "system-vnc1l-grinder-PRO-branch", which restores
    the use of the beta-brite sign.
  - Tour multiball balls in play changed from 3 to 2.  Jam multiball balls
    in play changed from 3 to 2.
  - Changed shook me car art.
  - Added new T.N.T. art for the background hurry-ups.  Cleaned up T.N.T.
    mode.
  - Cleaned up ticket stubs (separated the artwork and centered the text).
  - Put in new gear artwork for combos and super loops.
  - Corrected the render order of the girls and Angus for You Shook Me.

V1.21 - February 2, 2012
========================

- Initial release.

Has anyone got a headache AFTER READING ALL THAT.LOL