Hard to say, it apes DM in feel perfectly while being completely original with the traps and ideas.
Good original puzzles.
Used most of the dungeon!
As playable as DM.
One of the first dungeons, still some nice bits like the VI alcoves on level 6.
At the time (I was a CSB virgin) fighting those three dragons made me yell at the screen, groan as my wrists ached, then improve my game about 100% - great fight!
Just feels so DM!
One of the first I played when I found the community after so long away from DM, reminded me why I loved the game.
The dragons' lair.
Can't think of one!