The book starts from the basic exploration, kingdom/city building and mass combat rules as presented in the Kingmaker AP Chapters 1, 2 and 5.
As written it's quite useable and has a few interesting changes as noted in previous reviews, such as the change in the square miles of the area a hex encompasses. Trivial point: the area of Washington D.C. is a bit under 70 square miles, so you can fit more than 5 of them in a single hex.
The kingdom building chapter adds in a substantial expansion on "farmlands" from the original rules, changing this to "open spaces development". This is the best part of the entire book, one I am adding in toto for my own campaign. This gives a reason to remember where your various landmarks are at on your kingdom map, as you can do something with most of them.
The revisions in this book for building cities and the changes in the actions by size of kingdom in my opinion are unnecessary.
There are a few new buildings, some of which are "odd". The majority of the new buildings are underpriced variants of the tradesman building in the regular rules that don't require houses be adjacent. The Keep is a variant of the Barracks that costs too much. The additions to Castles are nice, although the moat is badly explained and the 'wards' one is either overkill or far too easily bypassed by other means. Best to remove it from availability.
Mills are incorrectly assumed to only be used as a lumber mill and require substantial water access. More mills are likely built and used to grind grain than mill lumber and can be build on a much smaller river or stream than can a pier. As these rules stand, you have to have a carpenter for quite a few important items - which means in order to build various stuffs you will want every city built on a water border to build the mill that the carpenter requires. This doesn't really work well... Some of these discrepencies derive from the original material.
The militarily-required buildings are generally unecessary as well, although they are tied into the mass combat section of this book.
The mass combat system is a nice attempt at changing the admittedly basic one presented in Chapter 5 of the Kingmaker AP. The consumption costs are generally far too high, especially on a weekly basis. The training system works well enough, although using it as-is might not be so satisfactory for some.
There is a new tactic for victorious armies to learn and 4 new resources to upgrade armies with. These are also good additions and ones I plan to integrate in toto. I suggest that the poison resource inflict damage to the army using it as well unless that army is comprised of creatures with the poison use class feature or that are immune to poison.
There are several special abilities added - only Mercenaries is worthwhile. 'Bleed' is best left as originally presented in Kingmaker as part of the 'poison' special ability, while 'Crusader' is too subjective. Everyone will argue that all of their armies are crusaders to shave those consumption costs down.
Vassal armies I think are a good concept that in the book that is not well executed.
The army construction rules present an interesting concept: limiting maximum army size by 'method of conscription' - based on whether the army in question is conventionally recruited and trained (marshal), divinely acquired (planar allies?) or 'arcane' (which covers all the rest of them).
There are several new feats presented, most pertaining to govorning your kingdom or leading your armies. They are good enough to use, although Sickening Strike I would remove. Dirty Trick is already able to do this and doesn't quite require the "feat taxes" to acquire the feat. The rest of them seem fine, although Mountain Strike I would caution against unless you are willing to have some of your bad guys get it too.
The mass combat spell section has some problems as well. I cannot recommend integrating it as-is. The summon army spells are - while written for entire armies of wizards/sorcerers/clerics/druids - an especially bad idea. The effects of summoned monsters on this scale are sufficiently covered by that army's "spellcasting" special ability.
The only two non-army spells of note (besides the two that deal with scent) are (a) magic wall - which omits the very important detail of how much it costs and what the minimum caster level should be to make it permanent; and (b) wall of tentacles.
My beef with this supplement's army building rules are identical to the original ones - purely RAW they are way too easy to abuse. Armies of hound archons are the same cost as an army of 5th level fighters - both are a base CR of 4 as a Medium army in this example.
The same complaint goes for armies of golems, pixies, rust monsters, great wyrm dragons ridden by 20th level wizards and so on. There should (in most campaigns) be a hard cap on what one can recruit and train in such numbers.
This supplement attempts to reign that in by the consumption cost / week of resources = same as the cost to purchase. This really doesn't work well, as it makes armies too expensive without addressing the core problems.
The magic items are largely fine - but I caution against the trio of statues. As they're written, a group could plant one of each in each city for pretty cheap and rachet the kingdom's bonuses up even further. In a nutshell, one park per city(6 BP, most often either 3 or 1 BP) 'unlocks' access to these statues. Presumably the PCs are able to craft them, so they cost half. The +1 statues are a bargain at 2.5 BP each - the reason? Each *city* can have one of each statue in their park. I recommend house-ruling the highest such bonus provided by these statues be applied to the entire kingdom as an enhancement bonus. Otherwise, one set of +3 statues - at a 'retail' cost of 135 BP - provides the same benefit as placing a set of +1 statues in each of 3 different cities at a 'retail' cost of 22.5 BP. For the same price as one set of +3 statues, you can acquire a +18 to Economy, Loyalty and Stability for the entire kingdom, provided you have 18 cities, which is not hard to do.
