Love this adventure. It has a great macabre horror element to it, which is always nice.
The Puzzle is a fun one that anyone can enjoy and solve (it just might give them a headache ;) ). I definitely recommend encouraging the entire group to work on it and definitely use the suggestion of dark thick sleeves for the puzzle pieces, I went with dragonshield card sleeves as they get the job done.
The Combat can be a fun challenge, and perhaps punishing, depending on the party build and the DM.
The only complaint I can make is that I wish it was longer.
I would highly recommend this adventure, whether you're running it or playing through it.