This book really makes the Underdark come alive. Unique locations, weird and interesting creatures and personalities, exciting encounters - and all with a very consistent and cohesive wrapping. I think the designers did a great job with the presentation and the material, and the amount of energy invested in the book leaps out of the pages.
For Experienced DMs
Tyranny of Dragons and Princess of the Apocalypse felt like massive adventures, but I can see an inexperienced DM running Tyranny of Dragons, or even Princess of the Apocalypse. Out of the Abyss will stress out an inexperienced DM, and might prove to be a challenge even for an experienced one. The very first encounter has a dozen well detailed NPCs, each with an agenda of its own - and the PCs are going to interact with them all. From there, it's a sandbox. Non-linear, and very open. The amount of information the DM needs to digest before the game is truly immense. That said - the book is very well written, and the setting screams to be read, enjoyed, and played. The Underdark is a dangerous place for 1st level PCs, so you can expect a lot of roleplaying moments, as well as tense combat situations - and a good DM is needed to make sure a TPK doesn't happen 15 minutes into the session.
A Sea of Madness
The book makes use of many special rules presented in the Player's Handbook, like madness, getting lost, foraging, crafting and more. The Underdark is portrayed like never before, with alien landscapes, bizarre personalities and unearthly locations. The book provides great advice on how to narrate travel in such locations - and how to bring the Underdark to life while traveling days from one location to another. And don't forget - the demons are Out of the Abyss, so this dark, evil place have become even scarier than before. Players can expect to interact with creatures considered natural enemies of the surface-dwellers if they want to survive, and the constant threat of a knife in the back is ever present. Role-players will have tons of opportunities to shine, and combat encounters will require a lot of cooperation and thought to escape death, imprisonment or both...
"I ASKED R.A.SALVATORE, ‘DID YOU INTEND FOR THIS TO BE AN HOMAGE TO ALICE IN WONDERLAND?’" (Chris Perkins)All in all - I was very excited to get my hands on this book, and even more excited to see the great material to be found inside. The quality of adventures is constantly improving, with a positive slope from Tyranny of Dragons to Princes of the Apocalypse - to Out of the Abyss. I think Wizards are finally doing it right - and I really hope their Aboleth Overlords have even greater plans for the future!