Too many ads
There are in game purchases if you want those so the developers can make fast money. Then there are the ads. When you select to view an ad you know what you're being offered for watching it... Which is good, however...
As you progress through the levels and rise up the leaderboard there are upgrades made available to your base. When an upgrade is available you have the option to wait for a period of time or watch a video to speed the process up. The upgrade period gets progressively longer. So as I write this review, I'm up to 11 hours. I now have a choice, I can wait 11 hours for the upgrade to take place or I can watch ELEVEN ads (yes, you did read correctly 11!!!)... So it seems that the developers reward you for playing the game for longer periods by making you watch more, and more ads.
There will come a time that I won't be bothered watching these which will mean they get zero income from me.
Looking at other reviews, I'm not alone on this. Developers, you need to choose between some income and no income. One of these will put food on the table, the other will not. Please consider treating your customers better than you are at the moment.