So as a disclaimer, I am friends with the author. That said, I do think this is one of the more fun scenarios I've played. It really walks a fine line between the silliness of Goblins and the horror of them, and I enjoyed both playing it and running it.
I have to give a word of warning to all GMs, warm up your vocal chords before you run it, because I had a hoarse voice the next day. But it was worth it to sing the songs. But enjoy it, Brian's one piece of advice to me for running it was "ham it up" and it's really true. This is a good scenario to bring out the RP in a table.
It's not the most difficult scenario for this level, but I think it hits a good level. The session I ran had a full table of level 1s and one level 3, two people went down on the last round of the last encounter (but not dead), so that worked out pretty well.