They thought of everything. Not only are the encounters very clever, they are also quite detailed, and can be scaled for slightly lower or higher level parties.
There are descriptions that can be read to the players, so that too much information isn't given away, and there are numerous sidebards describing related topics.
Some puzzle encounters describe how to create similar puzzles, so that the DM can generate his own dastardly encounters.
On the downside, the maps are only adequate, and nothing to write home about, and there is not much other 'flavor' art.
Still, this is a really worthwhile purchase, and I'll be including some of these dastardly encounters in our next adventure!