I only played the original one. Good game. Didn't follow the series though. I think the highlight of that game was going to Rimuldar (or something like that) and sneaking in there to buy keys on the lowest possible level to open up all the hidden chests around the beginning areas, and then trying to sneak down to Hauksness to get the best armor in the game in the destroyed village. And then there was that whole cursed belt in the cave that you had to go back and remove before it killed you OR sell it somewhere for big bucks (can't remember where though). The Dragon Lord was a big letdown though. The picture on the cover of the game made him look much more formidable than he actually was.
Ah, Dragon Warrior. Such a great series back in the day. I played all of the ones on the NES, but barely remember them at all. The first one was really hard. I know I got to the final boss, but never defeated him.