Like the Leaning Tower of Pisa, iso is a wonder to behold even if the foundation is a little shaky. Straightforward match-three gameplay ensures an easy introduction, but a perspective shift provides challenge as well as style.

With the sort of gameplay that will seem familiar to anyone who has spent any time playing Tetris, iso fixes on matching coloured squares that fall from the top of the screen in vertical groups of three.

Your only actions are to move them left or right as they drop. You need to carefully choose their position so the blocks line up in groups of three, vertically, horizontally or even diagonally. Alternatively, you can change their order, tapping the screen to rotate the blocks downwards.

When you match three blocks of the same colour, they disappear. Those above fall down to take their place and, hopefully, set off a chain reaction that clears other trios from the screen.

It's a method of play that doesn't rely on time ticking away or an unnatural acceleration of the pace. The blocks simply glide down from the top, your only hazard being the doom that awaits you if your towers reach the summit.

Well, it's less of a “doom” and more of a Game Over. iso is a one level, last-as-long-as-you-can wonder, the sole challenge being survival and your only motivation a high score. That's how games used to be, and iso does a wonderful job of bringing that same logic onto iPhone era. An isometric perspective adds fresh dimension, though not without issue.

Sadly, it's this very view that puts a dent in what is otherwise a solid stab at block puzzling. This perspective makes it rather hard to pick out diagonal matches, making it all too easy to bring a pile down (swiping the screen downwards with your finger brings the cubes down at pace, helping your score) in the wrong slot entirely.

Spotting the right matches takes some concentration, which is possible when the gap between the top of your towers and the top of the screen is wide. When things get tighter, however, split-second decisions are imperative. It's a factor that makes iso's bold, smart styling a little regrettable - seemingly the smallest of design choices has an occasionally acute effect on play.

If you can tune yourself in to the game's particular groove, it's something you can tap away on in between meals, on the bus, or in any spare moment you have, each time striving to top your previous score. While the isometric view does create problems that require patience to overcome, it does give the game a unique feel.

Like the Leaning Tower of Pisa, in fact, iso is a visual treat, but one that isn't quite as stable as it might first appear. With competitive pricing and accessible gameplay, this is a cheap puzzler we're leaning towards.