Most of the levels have unique solutions. There are 200 levels ranging from beginner to master.
At the moment, I've done 150 levels. I positively love this game and it's totally free - provided that you do all the levels and not skip around. The ads are annoying, but that's still okay because I can't get enough of this.
Another negative: the program crashes every so often. I uploaded the latest Ipad software, and the game still crashes. But I keep playing it.
Let's end on something positive: these puzzles are hand-crafted.