First off, fantastic game that is worth your ten dollars of nintendo points.
Second, it gets HARD as hell.
I'm at the boss fight I guess of the third act. I've loved the game so far, and replayed old levels to completely max out every monster and tower upgrade possible. But this level, wow. Strategy game, that is as fast on reflexes as street fighter two. I went online to check if there were faqs with advice (walkthrough not so possible for this game), and to my surprise the faq at gamefaqs ends right before where I am.
Even checking the message boards no one even discusses past act 3.
I love this game and cannot accept that I will get no farther, anyone here actually beat this game?
(don't take this rant as reason not to buy this, you should still buy it)