The game genie did not give you a menu, you inputed codes which would persistently modify the memory map of the cartridge allowing for things like 99 lives or max Hp. The “menu” you describe was a booklet containing every game and a list of code changes.
Of course you could write in your own codes and make your own hacks but a lot of the time you ended up with garbled graphics or an unbootable game. They did keep this developer documentation to a minimum and this was before the internet. Although my local BBS had an ascii document detailing game genie’s internals and how to write your own codes, it was far from the reach of most 10 year olds
The game genie knockoff clone (I forget the name but remember the ads lol) had all of the codes in memory and as such gave you a menu to choose from
Of course you could write in your own codes and make your own hacks but a lot of the time you ended up with garbled graphics or an unbootable game. They did keep this developer documentation to a minimum and this was before the internet. Although my local BBS had an ascii document detailing game genie’s internals and how to write your own codes, it was far from the reach of most 10 year olds
The game genie knockoff clone (I forget the name but remember the ads lol) had all of the codes in memory and as such gave you a menu to choose from