As others have noted, the black and white dots were confusing at first. Once I read the developer reviews that they only relate to the number of right digits & places, but not their position, I figured it would be impossible to solve and *almost* deleted the game.
Then, I tried different strategies to solve for the digits and found that it is in fact solvable and is just challenging enough to keep you from getting bored with it. I realize now that if the dots gave you the position of the correct digits, it would be much too easy and would become boring fast.
This game will make you think and it’s fun because a round is fast. As another reviewer stated, if it had landscape mode on the iPad, I’d give it 5 stars.
It’s fun - give it a try, but just make sure you understand the rules!