First - If you have further questions on what was actually done, take a look at my two other videos on it
Creating a Mr Gimmick Cart
and This one I did on Earthbound, showing some wiring that is commonly required.
There is a fabulous website that has tons of information on each of the boards different games use: http://bootgod.dyndns.org:7777/
I picked up a super common game for $1 USD the other day, and honestly it was too dull to play, so this is how to deal with such a beast ;)
So far, I give the gameplay a thumbs up !