First, all of the puzzles are solvable on iPad (puzzles may have more than one solution). The games concept is unique and engaging. The downside is the very real possibility of getting stuck less than halfway through the game, since it offers no hints or level-skipping. The levels dont necessarily ascend in difficulty from one to the next; they build more generally as you learn new concepts and techniques, with an occasional super-stumper thrown in. Unless youre very confident (or have found a walk-through), purchase with caution.