I ran this adventure and my players enjoyed it. The players did take advantage of the some of the venting terrain features, and saw that furtility in trying to take on the masses of creatures that they encounter. The players were challenged by Biscuits and also the HH's, but Seabordt and his guardian truly made things dangerously challenging and pushed them. I liked that the planar environmental effect, although my party wizard sent a sunbeam (brust) to deal with most threats! They were still challenged though. My rating is based on the fun factor of the module for players. As a DM, I had to open DotMM in order to read up a little more on the area the adventure takes place in, as well as review the DMG for other excacerbating elements. All-in-All, and ample finish to a good run.. .now I will keep my players down here and have them continue through Vanrakdoom! Run it as part of the series for a complete adventure arc...