Game will keep you going for hours trying to get that perfect deck of cards to crush your opponents with
The game is a polished version of it's predecessors beyond that. There is a lot more artillery and ways to really steamroll your opponent in the late game. Early on, you'll find yourself making a lot of a unit that is available to you early, just to have some sort of fighting group. If you can harass some of your opponents when you're in the 2nd age and they are in the first or second, you can really make the rest of the game a piece of cake in single player.
The campaigns are very interesting. They keep you wanting to play the next one when you are done. There was no really, really hard mission at the end of it. They introduce you to the game very well.
The computer says funny things throughout the missions. They sometimes put up a tough fight if you haven't bothered any of your opponents early on.