As others have already pointed out, this is a very detailed and well researched work. There are plenty of martial feats to showcase the differences between fighting styles. Although I find it somewhat out of place that there are 2 feats with japanese names, for example Nukitsuke could have been translated as Fast Draw, or something like that, and Niten Ichi, I guess, is a fancy way of saying Two-Weapon Fighting. Thenagain those english terms are probably part of the original OGL... Also the infamous Mordhau technique is sadly missing from the list ;) The skill list is very thorough, almost to the point of being exhaustive. All in all I find this a very useful resource to plunder for my own games, and there's even an appendix that gives us guidelines for adapting the system to other OGL games.

TLDR: If you like low fantasy and history-based RPGs GET THIS NOW!

Codex Integrum is an incredibly well-researched tool to create RPG adventures based on a late medieval theme. It can easily be adapted and integrated in other d20 systems, or campaigns that want to have a realistic medieval or Early Modern tone to them. However, where the Codex Integrumm Player's Guide really shines is if it is used solo or in combination with other Integrum supplements to create low fantasy, historical or pseudo-historical campaigns. Unlike the often frustrating characters of other games that do that, here you do not play a rat-catcher, but your character is always useful and not in a narrow context.

The various rules provided all support the creation of a narrative that is equally realistic and immersive. Melee combat is at the core of the Integrum titles and this book is not exception. The depth of rules, background and tables provide a well-curated, modular toolbox for the GM to pick what they want to implement in each game. If you want tools to create a new campaign that feels 'medieval' or want to add such elements to an already existing game, the Player's Guide is an invaluable tool. At the very least it will give you awesome narrative ideas. If used in depth I foresee a rabbithole of wikipedia history pages.

If you do not like medieval themes or martial arts you are probably here by accident and this game is not for you.

I bought this, on a whim, along with the fighting guide. I was fascinated by the combat system, and so it made sense to dive in with both.

The research that has gone into this, is evident. So, it is a fantastic resource for those that appreciate adding historical aspects to their game. I use a fantasy map, and use many of the classic character types, but this has given me ideas flushing out my universe.

i am not ready to run a purely historical setting, but I have always operated my campaign with the Tolkein mindset of one foot in fantasy, one in reality. So, I temper my fantasy elements, but I have no problem adding rules and material based in history.

So, this is a wonderful compendium to get material for just about any style of campaign. Definitely for history folks, but this would work well in a fantasy world as well - I'd recommend for either setting.