It has all the good stuff from Populous 1, and throws in heaps of cool mythology. It is the best god-game ever created, mainly because it strikes a perfect balance between you and your subjects. It is incredibly fun, there are countless strategies you can employ (thanks to a tonne of god-powers), and it really feels like your little worshipers have simple little minds and goals of their own.
Populous 3 (The Beginning) felt absolutely nothing like a Populous game, and completely ruined the series. Why anybody would want it is beyond me.