It's more like Wizardry or Shining in the Darkness than Dragon Quest or Final Fantasy. In these types of games there is no overworld or epic-quest. You just explore a HUGE dungeon, slay monsters, and look for better items. This game also has a random dungeon so it changes each time you play.
The storyline gets revealed each time you die, but really the game is all about leveling your character and finding new items. In other words it is all about gameplay and not cutscenes or storyline.
Sounds like you are not into oldschool RPGs so you will likely not enjoy it. So just rent it so you can see for yourself.