Below are a series of videos detailing the game's basic mechanics, from building Towers to dealing with certain types of Creeps. Feel free to let us know what you think. You can e-mail us, and we also have discussion threads on the TIG Forums and TouchArcade if you want to leave feedback. We're pretty easy to reach, really.
Keep in mind that the single-player version used here is a bit outdated in terms of artwork, but it should still be efficient in explaining how the game functions on the defensive end. Enjoy! We're working hard towards a shiny new beta around the close of June.