Dungeon like PRG

I am thinking about making a map epic size.3 heroes enter a dungeon FULL of creeps and traps.They have to kill a dark lord and take his items.

Yes idea is like other but my own game has a little bit of difference.

In the start map divides to two paths.Either of them has its own story.

-Atmosphere and terrain
-Hero abilities.
-Unique items.

What do you think?