Nothig really good, but nothing too bad is, how basic it is. Literally every JRPG after this did something better.
It is far away from horrible, stands out, how this is the basic one a lot of games built on.

The game world is far away from beeing bad, but feels empty from time to time.
Most of the dungeons are, surprisingly, easy to navigate and not confusing.

What has not aged well is the storytelling. For me at least.
The king declares that the Dragonlord must be stopped and his daughter got kidnapped. Then you have to deal with it yourself.
You get lore, or even an idea of what you might do, through rumours that you learn by talking to each person in the towns.
Once you've done that, however, there's no guarantee that you know what to do now.

Additionaly, there is a lot of grind in order to level up and buy better gear. I'll just put that down to the time it was released.
There was very little space on an NES module and somehow you had to make Dragon Quest last longer than an afternoon.

We are also only able to save at the castle, which would mean a lot of backtracking.

I used some of the benefits we have nowadays: a guide to know what I am supposed to do, quicksaving and fastforward.