In reality most of the complexity lies in how "close to the metal" it is, not so much on the language or the programming techniques per se. Basically, to progra

In reality most of the complexity lies in how "close to the metal" it is, not so much on the language or the programming techniques per se. Basically, to program for an old console with limited hardware like the NES, you have to understand how the hardware works at a relatively low level to do something with it. There's no "drawSprite" function that you call and be done with, but rather you have to understand what the video processor can do, how do your feed data to it, how you compose a sprite in a layer, etc etc. So you learn how the different pieces of the hardware work, how do you instruct them to do things, what are their limitations and so on. And once that clicks, it's not particulary more complex than writing modern code. Like programming today, it's less about typing and more about thinking about how all the dots connect together towards doing what you want to do. You do end up with a lot more code that does a lot less, since there are no abstractions and you do everything by hand. But otherwise it's something that anyone with aptitude for programming can pick up.