Well I have a lot of the work done for supporting two players. Saving the state of 28 cubes and 14 disc positions wasn't too difficult and time consuming. I still am spoiled by machine with more memory where you can just afford to save an entire screen, for example.I am still trying to find one of my Ball Blazer carts to see make me a Beef Drop cart. If the cart looks like the board and schematic online it should be as simple as removing the ROM and replacing an EPROM, installing a 7404 in a place for it, and snipping a jumper.