Some key features were missing in the Pathfinder Core Rulebook, in my opinion.
I got the Gamemastery Guide shortly after release in March 2020, and here is my first impression after a one-hour flip-through of the book:
The short version is that the Gamemastery Guide is all about tools and customization. My favorite parts are likely to be relics, the improved NPC and monster design rules.
The layout is growing on me, although I am still not a fan. The artwork is top-notch.
The first chapter is lots of game master basics, like running encounters, minis, mapping, exploration, and problem-solving.
More on downtime is excellent, I love that. Downtime is where the characters come to life, in my opinion.
The adventure design and campaign structure seem fun, and will probably be sections I will read in-depth first. I’ve given what makes a great adventure a lot of thought, and seeing Paizo’s ideas spelled out is interesting.
The chapter seems like a great read and should be useful for all gamemasters. This is essential reading really,
The Tools chapter is where I really get interested. Building creatures, NPCs, relics, worlds, settlements, planes, are for me considerable parts of the joy of running a game.
I am pleased to see Paizo move away from NPC level = CR, which never worked. NPCS are now statted as monsters unless you want to stick to the old ways.
Relics should be so much fun. Scaling items was my favorite part of Pathfinder Unchained (2015). Scaling items are now refined with more style and less math.
Victory points, influence, research, leadership, etc., etc. Some of these will be staples in my game, others probably unnecessary.
The variant rules include alternative ability score generation, alignment variants, deeper backgrounds, and 0-level characters.
Backgrounds should be fun, and is something the current Dungeons and Dragons is doing very well. The first edition traits was a great idea, was fiddly, and later additions added lots of detail, but the initial problem remained. The second edition backgrounds appear much more elegant, and this variant system allows you to mix-and-match, although at the danger of reintroducing fiddliness.
My main takeaway from this chapter is the 0-level characters, which should work very well in the Core Rulebook, and here it is explained in more explicit terms. Nothing new, but well done nevertheless.
The NPC Gallery
The last chapter is the NPC Gallery, which should be super-useful for my games. Bandits, grave robbers, assassins, barkeeps, acolytes, cultists, and so on are old favorites. My only complaint that it is not nearly enough. Fifty more pages would have been nice.
A Verdict? Is the Gamemastery Guide Any Good?
Pathfinder is not easy to use, which probably was part of the reason for a new edtion. Pathfinder is a huge game, which is appealing and undoubtedly causes problems.
The 3-book standard, which PF really uses, is very costly for someone just checking out what roleplaying games are. I realize a new Beginner’s Box probably is in the works, but having everything you need in one book is very appealing.
You could perhaps argue that Pathfinder requires two, or maybe even only one book to play. Technically that is true, but I think the missing features make a complete Pathfinder game a three-book setup for the second edition.
So what is the verdict? I stress that this just is a first impression, not a review. You do not need this book, in my opinion. Absolutely not. However, if you are a passionate world builder, meaning a GM that enjoys creating NPCs, monsters, and the campaign setting itself, the Gamemastery Guide is an invaluable book. I could not see myself running a Pathfinder second edition game without it.