The Green Scar is a very inventive and compelling three-part adventure, but it could act as an entire campaign setting with the adventure acting as the skeleton underneath the setting. Somehow the author manages to create a jungle setting that is unstuck from time, where the players could find themselves warping in and out of the past and the future, and he fills this jungle and the town closest to it with plenty of other perils in addition to this without making the adventure feel bloated or complex.
The first half of the pdf deals with the jungle and the Stone Glade, the primary setting that will vex your players, but it seems more fitting to call this the first act of the drama that is unfolding for them. I think these first 30 pages have enough detail and interesting ideas that are enough to build an entire series of adventures off of, there is even a compendium class that fits seamlessly into everything. There are only two tracks of grim portents, and it would be easy for an enterprising GM to stretch out what is here or even add a few more. The second half of the book details the closest piece of civilization, the town of Brink, and there is a separate adventure here with a completely different pace and theme stretching between the town and an airship where an industrialist is going to destroy the jungle, and in so doing might also destroy a lot more!
There is a lot to like about the Green Scar. I like the dungeon moves, and how the dungeon moves aren't literally used for dungeons but instead for a jungle, a town, and an airship. I like the history behind the Stone Glade and the frogmen, though it seems like you would need players who are curious about it in order to reveal pieces of it, and I like the fact that each of the three parts of this adventure can easily be altered to stand all by itself. There are only two things I didn't like. First, the design of the download is not implemented very well. The maps come bundled as additional pdfs instead of jpgs, and there is a separated beastiary file which would work great as a little printable booklet, but the pages seem to be designed for a full 8.5 x 11 format. I kept imagining how the layout and the design of all the moving parts could work better and I take that as a sign that what was here was lacking. Second, the author spends several pages giving GM advice which is almost identical to what I've read in the Dungeon World rulebook and so I consider it unnecessary. Since these are technical complaints they are barely worth mentioning, as the adventure itself is very good despite them.
You can purchase the pdf of "The Green Scar" at DriveThruRPG