Fun game -annoying greed – Total Defense - Great TD in Stunning 3D Review

I enjoy the game but I'm ver annoyed with the short game length and constant demand to pay for upgrades/extensions. I upgraded once and within 20 minutes i was asked to upgrade again. Also annoyed with the fact that there does not seem to be any difference between the three levels of difficulty.
Review by poppyjacopo on Total Defense - Great TD in Stunning 3D.