The Islands of Purple-Haunted Putrescence (IPHP) is an OSR hexcrawl over a gonzo science-fantasy landscape populated with strange creatures, unique challenges, and deranged populations. IPHP was initially funded on Kickstarter and was one of those rare gaming projects that actually saw an early delivery.
The first half of the book consists of background information about the islands as well as lots of useful tools for inserting weird ideas and background data for the PCs. I would think of this part of the book as a grab bag of inspirational ideas and useful character building tools. Some players might balk at having a randomly generated flashback to their childhood or having a random personal connection to the islands, but with the right group of people this can be really charming and adds the to astronomical creepiness of the island's history. My favorite part of this section are the purple stones, a mechanical method to reward players for acting in the islands' interests (yes, you read that correctly), and the mysterious crystals native to the islands, powerful but nonmagical artifacts left behind by the decaying corpses of ancient wyrms.
The second half of the book describes the islands, hex by hex. There are lots of weird diversions scattered across the three islands, but there doesn't seem to be alot of effort made to connect them together in any discernible way. A constant theme is aliens from another dimension/planet who have crashed/landed and are up to some kind of mischief, or just minding their own business. There are pop culture references appearing just as often but are obscured in ways to not be immediately noticeable or recognizable, and some of the treasure includes items that might be found in our modern world which I found amusing, but some gamers might find distracting.
Some things I don't like:
1) There are sometimes multiple encounters listed for a single hex, but the map itself doesn't have distance marked so it's difficult to know exactly how big each hex is. One of the islands is said to be over 1000 square miles and a rough estimate means each hex represents about 30 square miles. A simple map key would have saved me the time to try and figure this out. This isn't egregious, but a lot of sections probably could have used some proofreading from a fellow gamer because there are lots of little things like this that seem overlooked.
2) There are lots of encounters that result in a save or die scenario, and I personally dislike these because I would either never use them or feel the need to rewrite them.
Some things I really like:
1) It's almost like having two sourcebooks because the first half is written with a general approach and many of the ideas can be used outside of a IPHP adventure. But hen you have the second half, which can be used as a straight up hexcrawl or as a collection of ideas to throw into your own games.
2) Despite the randomness of each encounter, each has enough detail to build off of and potentially create a whole session worth of adventure around. Played right, and this module could make a campaign last for months or years.
3) The artwork is great. There's a lot of great talent inside and I would love to see more of it!
4) Amazing Larry in hex 016
This book is a lot of fun! I don't see myself running it as a straight adventure but I can definitely see myself taking things from it frequently (and perhaps randomly) in order to spice up my own OSR games.
You can purchase both pdf and print versions of "The Islands of Purple-Haunted Putrescence" at DriveThruRPG