While arch rival Mario turned out to be a natural behind the wheel, it's taken Sonic a number of years and a whole bunch of aborted test laps to reach a similar level of driving proficiency.

But with 2011's Sonic & Sega All-Stars Racing, the blue hedgehog finally began challenging on a number of fronts - including iOS and Android. Even the fat plumber hasn't managed to do that yet.

Given the dramatic turnaround, it's perhaps fitting that this second Sonic karting game to come from Sumo Digital is called Sonic & All-Stars Racing Transformed.

Thankfully, the level of quality on display is pretty consistent with previous achievements.

OutRunning the past

SAASRT (another vowel, please, Carol) offers the same brand of arcade kart racing as the previous game, which means chunky primary-coloured tracks that riff on Sega games of yore, an impressive frame rate, and a handling model that calls to mind Sega's OutRun series.

Once again, a varied roster of Sega greats jump behind the wheel of their custom karts, with the emphasis on initiating sweeping powerslides (there's a dedicated button for it), hitting boost points, and utilising destructive power-ups.

All of this is done through two parallel campaign modes - the standard Grand Prix (three races per cup) and the daunting World Tour.

In the latter you'll find yourself tackling a variety of challenges, from simple races to time trials to special time-limited checkpoint runs.

Balanced setup

In all of this, Sumo's supreme sense of balance again comes to the fore. Whereas other kart racers (including some of Mario's efforts) frustrate with overly disruptive power-ups and cheap rubber banding tricks, SAASRT always remembers that it's a racing game first and foremost.

Even the most vicious weapon will only slow you - or your rival - down momentarily, and pretty much every weapon can be fired behind as a defensive measure. Meanwhile, there are numerous ways to pick up an extra boost of speed if you're skilful enough.

Aside from those fixed boost arrows, powersliding builds up a three-stage boost mechanism. Pulling off stunts will also give you a quick nudge, whilst initiating a stunt mid-transformation gives you another boot up the jacksie.

Karts in disguise

Ah yes, transformation. SAASRT's biggest new feature is the inclusion of two new vehicle types - boats and aircraft. At set points in most tracks your kart will automatically transform into one of the above in order to negotiate a radical shift in the terrain.

While aircraft are nimble and direct, with the tracks opening out accordingly, boats are more sluggish and unpredictable.

It's an interesting mechanic that undoubtedly lends a new flavour to the game, but I couldn't help noticing my relief to get these sections out of the way. It's not that they're particularly tricky - they're just not as much fun as the karting sections, and at worst they serve to break the momentum of some otherwise excellent track design.

These alternative means of transport also don't seem to work quite so well with the virtual or tilt controls on offer here. Indeed, SAASRT is one of the biggest reasons yet to invest in an iOS 7-compatible control pad.

Even played with the somewhat ropey MOGA Ace Power, the game suddenly transforms into a PS Vita-standard arcade racer complete with manual throttle controls and responsive steering. It's annoying that the menus don’t alter accordingly (you still have to touch them), but that’s a minor quibble.

Time for a service

SAASRT is another game to incorporate in-app purchases, which isn't particularly surprising even if it is slightly dispiriting. Still, Sumo's fine sense of balance is again on display.

We spent several hours with the game without once feeling like we were being coerced into spending real cash. You can dive into the virtual storefront and unlock all of the characters ahead of time, or purchase stars or rings to buy items, enter events, or upgrade your kart, but the former is unnecessary and the latter can be achieved through general play.

We haven't reached the later events at the time of reviewing - this is one content-rich game - so there's a chance SAASRT could descend into a grind-heavy trudge for the frugal gamer. But we've played enough to say that this would represent a surprisingly dramatic tonal shift.

Indeed, Sonic & All-Stars Racing Transformed seems to be the work of a developer that’s completely attuned to the iOS platform. Like the recent Ridge Racer Slipstream, it's a nigh-on essential arcade racer that wears its big-name console IP badge with pride.

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