Interesting slightly related note…I used to own an NES that displayed some games incorrectly. One of the games it would display incorrectly was Mega Man 2. On stages like Air Man and Bubble Man the backgrounds were not blue but black. I should have been really upset, but one the advantages of this flaw was that it also showed the location of hidden content because those sprites still retained their blue backgrounds. So this allowed me to know where the hidden platforms were before they appeared. Just thought I’d share.