Simple but challenging tower defense game. Find it too easy? Try the insane level. Find it too hard? A walkthrough can be found at www.secondgeargames.com This is a fully functional ad-supported version. You can also find an ad-free version of this game on the Market.TOWER PLACEMENT:- select the tower using one of the buttons on top of the screen;- tap the screen where you want your tower to be installed;- if you want to adjust the position, touch and slide until the tower moves a little in the desired direction;- press confirmation button to install the tower.