Dwimmermount is a classic megadungeon and old-school campaign setting presented for use with Labyrinth Lord and other D20-based fantasy role-playing games.
I have followed and been aware of Dwimmermount when James was running this homegrown campaign, and sharing the details on his blog. I was excited when he decided to do a Kickstarter to publish the material. After a long wait, the material was published, and I have enjoyed reading through the Labyrinth Lord edition of the book. I also have the illustration book and map book, which enhance the enjoyment and utility of the main material.
Dwimmermount is more than a mega-dungeon. It is a world, a rules extension, and a epic story. I have enjoyed reading the material, and coming to understand that great amount of work that was done to create this product.
I particularly enjoyed the last few levels of the dungeon, and then reviewing again the history, and the many tools to make the experience a living experience. I really like the idea of the rival adventuring parties, and also the factions throughout the dungeon.
I look forward to using this product in my own gaming.
This 10-level mega-dungeon (plus surrounding areas) targets a Barsoom-esque science fantasy vibe. Some of this works for me, some of it (particularly the pop culture in-jokes) definitely doesn't.
I did like that much attention has been paid to offering many mysteries for players to explore and competing factions for them to befriend or oppose as they choose. I didn't like that many of those mysteries involve a whole lot of 'Tomb of Horrors'-esque "you pushed the wrong button, and you are dead" elements.
If sprawling, random-death OSR dungeon crawls are your thing, you'll probably like this much more than I did.