7402 freaks
Do you remember from your high school's logic algebra that every logic function can be build using only NAND (or NOR) gates? Looks like creator of this multicart did not miss that lesson!
And the unpopulated middle 7402 which inverts PRG-A19 but it's not wired to anything at all.
Optimization:
* Two of these 7402s could be replaced with single 74153
* If they get rid of bus conflicts (either by plkacing 256byte LUT in ROM or changing switchinf from data to address bus) and replaced 74373 with 74273 and added diode+resistor OR to enable it, another 7404 could be removed.