It starts off intriguing, because you can pick normal or hard mode and you get a bigger reward. This struck me as a fun gameplay mechanic when it’s not tied to some sort of mobile game. The dungeon when I went through it was pretty tough (I party wiped at one point, and lost a lot of gold “fleeing” back to town - though thankfully my progress to that point wasn’t lost, and I just had to get back to where I died to try the fight again, higher level this time as I found a side quest in town and leveled up doing it).
There is a lot of fun stuff to find in the dungeon, and from what I’m reading many elements may even be randomized. There are shrines, teleport points, various puzzles, NPC’s to encounter, enemies to face, treasure to be won and earned, a lot going on. It was a big dungeon too. Here is the map for my dungeon, not sure how different the layout will be for everyone when they get to that same dungeon.
I assume if it’s randomized there are always some bits that stay the same of course, but I don’t really know having only been through it once. There is a second dungeon I’m right outside of where I saved and took a break, so there seem to be a decent amount of them in the game. While the one I went through was part of the story, this second one seems optional.