Most played game on my PS3
Once you have beaten a level you will want to go back and get a perfect score. Once you do that you will want to play it on expert, again, until you get a perfect score. Some of these levels are REALLY hard on expect which for me is great! There are a few levels we have a dozen times before beating on expert, and dozens more times until we got a perfect score.
There is an online score board for the "ranked" (Normal) difficulty. There is no online multiplayer at the time of this review (3/4/10). If you like tower defense (TD) or real time strategy (RTS), you must give this game a try. Go through the training, get past the small learning curve and never look back!