After several redoes and hours of work, I have finally finished revision 1.0 of the game cartridge! It supports all chips from Macronix's MX29LV series (MX29LVXX), and only supports the regular bank swapping, so only 4MB maximum of memory is used. The next cartridge will have more bank registers to support larger storage.

I had to go to a 4 layer design so I can fit all of the glue logic used for voltage shifting and the swap register. The next cartridge will use a CPLD to handle most of the work, so the layout shouldn't be as complex. Here is a picture of the cartridge layout:

I uploaded a schematic of the cartridge as well. I have also uploaded the gerber files for anyone who wants to fabricate them.

So I examined the circuitry for the cartridges, and found that an address line is missing, so the cartridges are only capable of 2MB capacity. There is a little hack one can do to fix this, but I'll work on fixing that bug in revision 2.