I took the races that first appeared in Gostor: Amazons, Olympians (now renamed "Demigods", and split into Demigods and Favored who earned the attention of a deity), Medusans, Nymphs and Titanborn. I edited them to make them more balanced. I took the most standard of each type and placed it in the book. For example, only the maliad nymph appears in the book.
Next, I decided to spend time on clerics. Since I opted out of using many undead, giving clerics turn undead would give a class's main ability becoming useless. So I gave everyone of the Twelve, a domain of their own. These domains heavily change how a priest from Aphrodite plays versus a priest of Athena or Zeus.
There are new feats, backgrounds, spells, and a few pieces of gear.
One of the most interesting element created are for the greaves: legs, foot and arm protection. When you wear them by themselves, there is no bonus. If you wear them with a light amor, you gain a +1 to AC but your armor becomes medium armor. Heavy greaves do the same but bumps your armor to heavy.
Why should I care? Because this creates added variety in look and abilities.
The creatures in the book cover a variety of types: beasts, giants, monstrosities some legendary, other mythic monsters with from a variety of levels. I wanted to make this a good primer but not a full list monster book.
One controversial entry - actually twelve - one for each of the main Twelve gods. Yes, I provided stats for the gods!
There may be times when you get to fight them. However, defeating them banishes them to Olympus where they are ridiculed by the others gods. I debated about giving them a "sliding stat block" where they would have a CR 4, 8, 12, and 20 version so the gods "level" with the PCs. They are gods.
As the PCs grow in power, they will face different deities. I did put Eris, goddess of Discord, in there as a Challenge Rating 6 adversary, giving you a variety of level challenges.
Do what you want, make it fun, make it epic, create a new legend! That's why I wanted to do when I started this.
You can get your copy of the book today directly from DriveThruRPG: Olympia Campaign Setting.