I have not my self played Dragon Quest V, but as an avid gamer for over three decades, this movie still gave me a lot of good vibes and took me back to some old memories!
The visuals are stunning and only based on that, I would recommend this! It does however fall short in some areas. It feels a little "forced" at times, and the potential is more than what the end product shows.
All in all it was a pleasure to watch, and even though it is nothing revolutionary, it is a good-feel story with stunning graphics!