Dragon Warrior 4 is one of the greatest RPGs on the NES. Its a very long satisfying game and even has its own AI system.
Graphics-While there are no backrounds for the battles and there are no spell animations the rest of the game looks great on the NES. The monsters are well detailed and the characters and towns look good as well. Sound-The musical score is very well put together for this game. Each chapter has its own overworld theme and the town and castle music are very fitting. The battle theme is pretty good while its not spectacular. I liked the music in this game but if you don't just play your own music on a stereo or something while you play.
Difficulty-This game can be somewhat difficult if you haven't played any of the Dragon Warriors before. Some bosses can be a bit difficult and can require a bit of leveling. Enemies out on the world map aren't hard unless you wander into an area you aren't supposed to be in yet. There are puzzles in this game but they aren't very hard to figure out. It isn't hard to figure out where you're supposed to go in the game either even though you do get alot of freedom of exploration.
Overall-This is a very good game and even though it is hard to find and a bit expensive you should buy it if you're a big fan of RPGs.