When you play through the NES version prepare for a hardcore experience. It's the version I played through first, back in my prime as a hardcore RPG player, and I was pushing the limits of what you could do in the game without guides and prior knowledge to make it easy. But man, that last boss fight. It was an intense blow for blow with only one character alive for several rounds, hoping I killed it before it killed me. It's my most memorable final battle in a Final Fantasy game. Years later, when I played other versions of the game, it was like a sigh of relief that they were easier and I could enjoy the finer aspects of the game.