Really like the theme and flavor of this adventure.
While short, it has a lot interesting rooms and features. The map style is fantastic pencil and graph paper drawings with computer art framing.
The story arc is interesting and unique (at least I don't remember many like it). I think the concept of this small story leaving its mark on the adventurers is refreshing. I would like to see more adventures have unique touches like this.
I will mention 2 issues I had. They would not stop me from running this but I will need to get answers or develop my own answers before I run it.
I'm being a little vague on details to try to avoid spoilers
1) The transition from 2 to 3 seems... a little railroady. Most effects described would require a saving throw, but instead it was described in the text. I would not even mind having the players choose to fight the magic (with a saving throw) or choose possible death. At least it follows the mechanics of the game. Also minor point. THe final test... seems like a one shot test. If a group fails I can't see how it can be triggered again. Perhaps something just as deadly but less solid.
2) The reason the for players to be drawn to the events of section 3, makes sense (PCs have what they do not) but the effect of the ritual itself seems odd. I have seen many snakes in trees. I think I will have to figure out a different effect.