>pac man on the atari or snes is maybe less than 100kb

Off by an order of magnitude! Pac-man sizes:

    4K: Atari 2600 (it's bad)
    8K: Atari 800
    16K: Atari 800 Ms. Pac-Man
    24K: Original arcade machine (Z80)

BTW, Atari 2600 "Flappy" (4K): https://atariage.com/store/index.php?l=product_detail&p=1038