One of the best tower defense games out there
I love the leveling system and all the creative ways you can arrange/upgrade your towers. It's easy to learn, yet very challenging in the later levels (especially if you're going for a Brilliant rating for every stage). Nothing quite as frustrating as dealing with a ninja boss after forty or so grueling waves (accursed ninjas!).
There was one small annoyance that I really wish could be fixed though. I would have liked an option to somehow turn off those damn 'help boxes' that kept hovering over your cursor when it was on a piece of land ('You can build temples on rocks!' ect.). Somewhat useful for first-timers, but they quickly became a nuisance to me, especially when they obscured my view of the map while I was trying to keep track of some of the peskier enemies (ACCURSED NINJAS!).
Aside from that, I had a blast. I really hope to see a sequel in the future :)