I really do not see this as a 4 star game. The only sound effect in the game is a click.
When you see your base, there is no information visible on the cards. Instead there is a frame around each card which just takes up space without adding any information.
Even at full zoom you cannot see card details, only 1 icon is visible.
The same applies to the cards in your hand. In many iOS cardgames, including Ascension and Hearthstone, you can see what your card does. Here, only a badly readable description and a single cost icon is displayed.
In my view even the base game is just average (which is of course not the developer's fault), but the implementation makes this worse.
I would rate this at just 2 stars.