Sonic the Hedgehog review

When Sonic raced onto the App Store, our excitement was palpable.

We have fond memories of this game from 1991, when it shook up platform games with its breakneck speed. Even now, the design holds up remarkably well thanks to distinct visuals and superb levels packed with hidden areas and multiple routes.

The opening area, Green Hill Zone, introduces the core mechanics of the game in a mostly open landscape, which enables Sonic to build up momentum that carries him through 360° loops and up short vertical surfaces and, when curled into a ball, allows him to break through walls.

Not all of the 19 levels are about speed, though. The Marble and Labyrinth Zones, for instance, are slower because they rely on carefully timed leaps to avoid genre clichés of lava and water. The pinball-inspired Spring Yard Zone and the blisteringly fast Star Light Zone are the game's highlights, though. There's also a series of special stages where a curled-up Sonic tumbles through a constantly revolving maze in search of the Chaos Emeralds required to defeat his nemesis, Dr Robotnik. These areas are perhaps the game's most challenging, as you have fairly limited control to bounce Sonic off walls and towards his goal.

If you've already played Sonic with a physical controller, it may take a while to adjust to the on-screen directional pad. Having played it on numerous platforms over the years, we felt slightly less in control until we adjusted to tapping to make fine adjustments, rather than holding a thumb over the centre of the pad.

However, the iPhone version has a more critical problem with uneven speed due to slowdown and a poor frame rate. Turning off the sound improved this on our iPhone 3G, but it's a disappointing compromise given that Sony's PSP handles the game so effortlessly. The credits reveal this is actually the original code running on an emulator, rather than rewritten from scratch. If the game's icon, labelled Sonic 1, is Sega's hint that the rest of the series is coming to the iPhone then it needs to iron out this issue.