The game itself is nice and simple, true to the "real life" game, but is lacking a little in a couple of ways. Firstly, the app occupies only a small part of the screen, making it quite small and fiddly so it's easy to touch the wrong "marble". Not a problem, just irritating. Secondly, when you've completed the game, or gone as far as you can, the box comes up with what looks like a normal end-of-game "OK" button, which actually doesn't do anything, so you have to use the buttons below the game board. Neither of these things stops it being a neat little game, and a good way to practice this kind of solitaire, but it would be so much better if it made use of the whole screen instead of skulking in a corner.
I had one of these games when I was young and played for hours trying to end up with one marble. This is the same game only this tells you how good or bad you have played the game. I still enjoy playing this.