Slydris

It's strange that there are so few games on the App Store that play around with the Tetris template. We've got match-three puzzlers coming out of our ears, and yet the most recognisable puzzler of all time sits relatively unmolested.

Enter Radiangames, which has taken the line-breaking basics of Nintendo's Russian legend and shaken them up a bit. The end result is an intriguing, entertaining, and remarkably clever puzzler that makes you think in straight lines again.

Unlike Tetris, Slydris doesn't involve steering single blocks falling down the screen and trying to arrange them into solid lines. Instead it sees you sliding blocks that are already settled on the screen, trying to fit them together in horizontal lines to make space and earn points.

The blocks you need to clear are one of two colours, and if you manage to make a line composed of blocks of a single colour you'll receive a points bonus.

There are three different game types. In Survival, you have a ten-second period of block arranging before another slew is dropped onto the top of the pile. In Infinite, every slide you make drops another few blocks in, although you can see what they are and where they'll fall.

The third type, Zen, is a calmer version of Infinite, lacking the escalation and urgency. This lets you practise without the pressure.

Each game type shares the same special blocks. Some can't be slid but will fall, others can't be moved more than once, and heavier blocks smash the things they land on when they enter play. Sometimes blocks enter from underneath the current stack, too.

Clearing lines powers-up a bomb bar on the right of the screen, and once it's full you can take out three rows from the pile.

Slydris offers a tight, often frantic puzzling experience, all wrapped in a neon package, and with a soundtrack that fits the on-screen proceedings perfectly.

Its balancing is just right, keeping you on your toes but never overwhelming you. A multiplayer mode would be nice, but otherwise this is a neat tonic for the match-three disease running rife in the App Store.