Personally, I love Dragon Slayer: The Legend of Heroes. It's a bit basic as GUTS said, but it's a little unique because it's like a traditional style 8-bit RPG, only with some new twists. The thing that keeps me coming back to this game is that it has a fun, simple story that just makes it fun to play through, making it a fun adventure that's just a little epic. There are only three cinemas during the whole game, but they are fantastic and the ending is wonderful if you ask me. The soundtrack is just decent for the most part, but there are some really outstanding tunes in the entire soundtrack, mainly towards the end of the game (My favorite being the ending/credits song, which I think is called "The Wind's Monologue"). I should also mention that this game is just midly hard; the bosses are typically going to take multiple tries to destroy and they are actually pretty fun if you are into turn-based battles. If you want a RPG that is a bit simplitic, yet a fun adventure, this is the game.
If you really want to play this game, I highly suggest skipping the PC Engine version and going straight for the Turbo CD/Duo version because it would be very hard completing the game without knowing Japanese since there aren't always cinemas explaining what's going on and reading will highly be required to understand where to go and to enjoy the story.