Space Invaders 78 Disassembly

This is my first post so I plan to make it a good one...

I've been enjoying Bob's Space Invaders for 3 months now.  Best port from arcade I've ever seen.  It's time to give back, so I disassembled the code, at least the logic portions.  The bit mapping is a mystery to me still.

As a direct result, we have an enhanced game play with Space Invaders 99 LIVES.  Guaranteed to improve your scores!  Will you ever lose all your lives?  Simple mod to the game code in three places, 63 hex = 99 decimal.  We know this because 6x16^1 + 3x16^0 = 99.  I suppose you could use FF hex and have 255 lives, but who cares?  I included PAL versions but how many users use this?

NTSC Space Invaders 99 Lives.bin
 SI_99LIVES_NTSC_50C0.bin   16K   6 downloads
NTSC Space Invaders 99 Lives.a78
 SI99Lives_NTSC_16K.a78   16.13K   9 downloads
PAL Space Invaders 99 Lives.bin
 SI_99LIVES_PAL_4C91.bin   32K   4 downloads
PAL Space Invaders 99 Lives.a78
 SI99Lives_PAL_32K.a78   32.13K   6 downloads

Christmas Quiz…Can you figure out how to do these variations?
> Disabling the player collision detect…
> When invaders hit bottom, the game isn't over, simply jump to the next level…
> Speed up bomb drops to max…
> Score points when you hit the bombs…
> Double fire like in the 2600 version...

Many thanks to Bob DeCrescenzo.  Efforting this disassembly project I have special appreciation for all the work you did.  It's extraordinary work you did.  "Maybe you guys can do something with it."   So we can, thanks to you.

Future Projects…
Does anyone have CENTIPEDE.asm?   PACMAN.asm?  I need those.  THX.

MERRY CHRISTMAS TO ALL!