4 stars: The app is quite-well thought out, and gameplay is interesting (and addictive). One thing that could be improved is adding tutorials/hints that explain in better detail how the game and its pieces work. Don't know how many times I blew up generators and coal burners before I figured out the generators needed to be upgraded to handle the heat output of the coal burner. That's something that could have been explained better.
3 stars: The ui looks great along with the rest of the game but the constant pop ups to watch ads are a little annoying. There's also trees and mountains in your way that you have to pay to remove or wait an hour 4 separate times to final remove it. (it wouldn't be nearly as bad if I just had to wait 4 hours and only click once instead of having to come back to the game every hour)...
3 stars: Graphics are great, but gameplay is extremely boring. The game should have a storyline to make it interesting or something. There should also probably be a cap on how many windmills/other buildings you can own, because being able to fill out your whole area with buildings in 5 minutes and accumulating cash faster than you can spend it isn't very fun
4 stars: Without spending any real money I was able to unlock all techs and free islands in under a week. There was no reason to buy the larger island and I'm glad I didnt. A fun little game that uses ads well to excel small bits of gameplay but not near enough content to warrant spending real money on...