It is not really undefined behavior when you have single hardware that will behave in a very well defined way. Old console games have all sort of hacks that all

It is not really undefined behavior when you have single hardware that will behave in a very well defined way. Old console games have all sort of hacks that allows them to do stuff that the system is not designed for. Having such a basic hardware with no security checks allows a lot of potential! Also isn't vertical split quite common? I would assume this is something the hardware designera thought of, not a game company figuring it out. They even put stuff like sprite 0 hit bit for this kind of tricks