Tower defense games seem to be all the rage now days, especially in the digital distribution scene. Last year, the PlayStation Network got its first taste of such a game with the brilliant PixelJunk Monsters. Later, Sony announced another tower game called Savage Moon. It is a very different game than Monsters proving that games in the same genre can be very different.
Savage Moon gives a background on why hordes of enemies follow a set pattern that march to destroy your base. Bringing a small story element in helped gel the gaming experience together, even if it isn't particularly deep. Another thing Savage Moon does well, right off the bat, is provide a tutorial that slowly gets you accustomed to the deeper strategy of Savage Moon.