I love free games that you can actually play without the annoying greediness of most games. This is actually a free game that you can play without upgrading or spending cash, but if you do upgrade, the reward is satisfying. Most free games dont strike this balance. The gameplay was smooth and bug-free. The graphics are top notch - though some of the angles are annoying. As others have said, the biggest flaw of this game is the sporadic varying of difficulty. Its not as progressive as it should be. But that is not enough to make this game a loser, its a winner all the way. One of the best free games Ive played.