on the real sega genesis.
all you doing is changeing is the 8th slot. when you gets an error in the game just change the 8th slot in to any letter or number to make the code better
and when you see what the code do write it down and delete the codes and put the codes in one by one and when you see which one that works thats the code you got.
also change the 2nd and 3rd slots to get a different code
when you see a different code go back and change the 8th slots to make the code better EVERY ERROR IS A CODE SO JUST KEEP CHANGEING THE 8TH SLOTS