I'm not sure why I bother, when there are better ways to play Pac-Man, but it's all a good learning experience, right??
Anyway, I thought the game was way too dark, so I brightened it up. I borrowed a lot of colors from Namco's Ms. Pac-Man NES port, and referenced the arcade game for other colors. The Pac-Man sprite got cleaned up, so his butt doesn't wiggle anymore. I also got my feet wet with a little ASM hacking, and got the extra lives indicator to use a different palette from the pellets (which required re-drawing the corner of the screen a bit!).
There's a nasty bug in the NTSC versions of the game that I tried fixing, but I'm not sure it's in my power. It seems like any data that is stored in RAM at 700-7FF automatically gets loaded into sprite RAM, so when the game boots up and zeros out that area, it looks there and loads a ton of sprite #0 at position 0,0, with palette #0 (so you see a yellow Pac wedge in the upper-left corner of the screen). The PAL version of the game seems to "fix" this by filling that block with EF instead of 00, which I assume just hides the sprites in the lower-right corner where you can't see them. I don't know how to copy the routine(s) over to the NTSC version without breaking the whole thing =)
So I gave up and made patches for both regions and I've been playing the PAL one. The music isn't sped up, but the gameplay is. I think I might prefer it that way.
The color I chose for the keys might be a bit dark, I'll look into it later.
I think there might be another bug on level 22 (the final looping one), because at the beginning of the stage, the ghosts stay in scatter mode for far too long. I'm not sure if I want to look into that or not, but one would think it would be easy to fix, once it was found.

Just for fun, I made a separate patch that just changes Clyde to green, like in Pac-Man VS.

Here's the patches, they're all for the Namco published versions from 1993 (not the Tengen ones). They might work on the VC ROMs, too. Tested in emulators and on real hardware.
http://www.mediafire.com/file/qazt8b4fpdcdaiv/pac-man_colorhack.zipI also threw in my TXT file of messy notes, in case they're useful to anyone.
Apparently my next project is an "LCD Ghosting Removal Patch" for the Nintendo DS Game & Watch collections. I'm about 17% finished with the first game. I'm sure there's a much faster way to do it than how I'm doing it =)