I love castle defender games, and this has got to be one of the best I have ever played. You start of as a Viking who has got to defend against various enemies. As the game progresses, new items and ways of using them become available to you- but your enemies also become tougher.
After you've completed the Viking levels, you move on. The second group you play as are the Aztecs, who were previously your enemies when you were the Vikings. The Aztecs can raise the dead, which is pretty cool.
You then play as the Chinese, enabling a special attack where you set a dragon on your enemies- arguably the coolest attack in the game.
There is also a Chief meat campaign, which is part of DLC for the game.
You control your fighters, by creating them at first and then instructing them to move forward. The aim of the game is to destroy your enemies castle, which you have to do at the same time as defending your own castle.
Not only is there the normal single player campaign, but there are 2 more single player modes along with an online option.
So, the game is your typical castle defender with the addition of different tribes to play as or against. I rather enjoy the game and therefore would suggest that everyone play it :D
P.S. Sorry for the short review, I was running out of time and had to pack for my holiday.