Idea is great, it's a shame it's so damn hard and beyond your control. To me, it seems there's a fundamental problem: as the waves get stronger, creating new/more towers gets harder as well. The longer you play, the more diversity there is among towers, and the possibilities for new matches decreases with the increase of diversity. The free moves aren't enough to counter this completely. If I didn't like the concept so much, I would have rated lower.