Clearly a labour of love for the developers. This DLC expands and deepens the game and it freshens up the metagame, opening up new combinations of cultures and new possibilities. Beautiful illustrations and awesome soundtrack.
Note to the developers: I hope they continue these 'cultures of X' updates. There are so many overlooked cultures in the world and I love to see them finally getting the spotlight. I've learned a lot from this game and even several archaeologists I know hadn't heard of some of these cultures. Now we're all reading about them!