Its very good but its not PERFECT. Too short!
The core gameplay remains pretty much unchanged in the expansion, though you do get to battle it out on a handful of new islands, some of which feel downright huge compared to those seen in Black & White 2. If you played Black & White 2, you can import your existing creature to Battle of the Gods, but if you didn't play that game, you can jump into the expansion immediately with a new creature. There are two new creatures to choose from, as well, boosting the total up to six. Regardless of whether you import an existing creature or start anew, you'll begin the expansion with a boatload of tribute points, and you'll have to purchase the buildings and powers that you'll start with.
Again, it's simple and easy to build up your follower's cities, as pretty much the entire game can be played without ever touching the keyboard. Just use the mouse to do everything from laying out cities to picking up and dropping citizens around on the map. You can also use the mouse to punish or reward your creature for its behavior, so it's easy to quickly train it to do what you want, from fertilizing fields with its manure to knocking down enemy walls.
The expansion does introduce new building types and powers. While it's nice that you can now build crossroad signs that help your followers move around the town more easily, this and other features don't seem to have a big impact on the overall game. Meanwhile, the difficulty level remains about the same, as the artificial intelligence is content to send platoons at you in a steady and regular stream, making it easy to crush them with your creature. Defeating the enemy is also unchanged. While it's possible to simply assimilate them peacefully by building a grand city that makes them want to defect, the sheer size of some of these maps can make this a long and drawn out process, since you'd need a huge and impressive city. So you can send your creature into the fray to defeat the enemy's creature and crush the Aztec armies, while building platoons to seize and capture Aztec towns. Whether you pursue a peaceful or militaristic approach, you'll find that it'll take you hours to get through each map, which is probably a good thing considering there are only a handful of new maps in the expansion.