Sonic The Hedgehog 4:f Episode 1 represents many firsts. It's obviously the first episode of a new series. iPhone and iPod touch are the first devices on which the game has been released.

It's also the first SEGA game for iPhone and iPod touch that shows it's taking things seriously.

Little else can be done to adapt Sonic's speedy platforming to the touchscreen - this is as good as it will ever get. That will suffice for most, yet for the franchise faithful weaned on a physical D-pad and buttons, this introductory episode is unlikely to be convincing.

Nevertheless, fun levels and decent controls are enough to define Sonic The Hedgehog 4: Episode 1 as a solid start.

Never-ending story

Dr Eggman's ridiculous plan to transform the world's animals into mechanised minions has you once again guiding Sonic on a hero's errand.

Four zones comprising four acts apiece make up the game, as do special stages that appear at intervals along the adventure.

The zones are a unique bunch from the familiar Splash Hill and glitzy Casino Hill to the dank Lost Labyrinth and steam punk Mad Gear Zone.

The themes are an appropriate throwback to the crazy stages of the old Genesis games and instil Sonic The Hedgehog 4: Episode 1 with a sense of authenticity. Layered levels with multiple paths, pipe mazes, disorienting loops, and an array of carefully placed boost gates and trampolines ensure the game feels right in line with earlier instalments.

The game is at its best when you hit speedy stretches when Sonic flies through loops and bounces his way from one trampoline after the other. It's a rush watching that blue blur zip across the screen.

Speeding ticket

Whenever those fast-paced sections end, the fun wanes. Jumping challenges requiring slow, deliberate movement break the game's flow. Boss battles are similarly stale in spite of the variety they offer.

Sonic is all about speed, and interruptions to the high velocity action are less like comic relief in a Shakespeare play than the unwanted ringing of a mobile phone during a performance of Hamlet. These slower sections ought not to be.

There are so many fun-filled moments: tilting through special stages in search of Chaos Emeralds, scrambling atop a massive boulder as it rolls through an ancient temple, and being pumped through steam pipes in Dr Eggman's secret base. For every questionable moment, a great one counters it.

Controls and performance

Thankfully, the controls don't put up much resistance. A simple analogue stick sits in the lower-left corner opposite a solitary action button in the lower-right.

The manner by which Sonic moves - slow steps when initially pushing the analogue stick or tilting your device, then as momentum builds he picks up speed - doesn't square completely with virtual controls or the accelerometer, but they're simple and effective, even if they aren't as precise as the real thing.

Performance issues have been put away, too - there's no noticeable difference between iPhone 4 and older handsets. While I primarily played the game on an iPhone 4, testing on a second-generation iPod touch brought up no problems.

Improvements can be made aplenty for the next episode - further tightening of the controls, integration with Game Center or another social gaming network, high-definition visuals for newer devices - though Sonic The Hedgehog 4: Episode 1 is a good starting point for what is shaping up to be a revival for the series.