There was indeed a lot "harder" games but I was also trying to include the element of poor design into the category of "difficult" seeing as a lot of the games back then required tedious movements and what not just to survive a single level. Glad you liked the post!
I had seriously thought of adding Ghosts and Goblins but one of my main goals was to show the poor level designs back then that added a sense of frustrating difficulty to a game. If we make another one, i'll easily add Ghosts and Goblins!