The interface is too cumbersome. Too many elements. I find my self lost on how to upgrade then to find out that upgrades are out of reach without paying. Or it may take u few years to reach that level for free. This game is geared to make the developers money. For me Ads are not a bother (this is where the developers make extra money) but recently all Ads don't fit on the screen and there's no way for me to close them and get my in game reward. It's only working in their favour.