These are usually fairly simple affairs which see you facing off against the impossibly moustachioed Sonic baddie Dr. In order to progress through the game, you'll have to clear each of the nine levels (divided into groups of three) as both Sonics - and upon doing so, you'll unlock a boss fight. You can take your time a lot more easily on the 2D levels. Actually, come to think of it, bar being able to curl up into a ball and spin really fast, old-school Sonic doesn't exactly have that many abilities to help him through the levels - but new Sonic's tricked out with a homing attack, which lets him zoom into enemies from a distance, and the ability to dash - helpful for clearing large gaps, and, er, running on water. Of course, with one being 2D side scrolling, and the other 3D, playing as both types of Sonic offers an entirely different perspective on the level, letting you see things you've never seen before, and reach parts you haven't reached before - it's much more than just a different viewpoint.ДЄpart from taking different routes through the stages, and seeing entirely different sections, each of the Sonics also have their own distinct powers, too. Meanwhile, new Sonic (taller and with more attitude) is all about speed, and zips through the stages in 3D, making things a little bit trickier than they really should be. Letting you take things as steady (or fast) as you want, you'll be bouncing off springs, rolling around loops, and dodging various moving parts as you try to reach the finish. Playing as old-school Sonic (who's smaller and fatter), the levels are 2D, side-scrolling affairs with a gentler pace. With nine Sonic games represented in total, and a level being taken from each, there's effectively 18 levels for you to play through here, as you can choose to play through each of them in one of two modes, each of which offers an entirely different perspective on the stage. Stuck in a strange rift in time and space, Sonic finds himself coming up against levels from the games of his past, from Sonic the Hedgehog way back in 1992, all the way through to the Wii's fairly recent (and really rather good) Sonic Colours. It opens with Sonic and friends having a nice picnic in a park as a surprise birthday party for Sonic (after all, he's no longer a teen) when all of a sudden, a vortex opens in the sky, and sucks Sonic and friends into it. Once you've finished the stage, you'll be presented with a cutscene that fills you in on the plot. In traditional Sonic style, there's something of an odd storyline here.

What follows is a 2D side-scrolling level that'll see you speeding through green fields, looping through loops, springing from platform to platform, collecting rings, and destroying the evil robotic monsters that lurk in the long grass as you whizz to the finish.

With the ever helpful small robotic blue cute thing Omochao on hand to help you out, you should have no problems getting to grips with the game, as one button does pretty much everything anyway - and Omochao's there to explain anything new players may not have come across before. Dropping you straight into the grassy fields of Green Hill, if you've ever played the original Sonic, it's a stage that should be instantly recognisable, as it's actually exactly the same as in the original, just remade with fancier graphics.

In something of a break from gaming tradition, Sonic Generations actually opens with a level.

Can i run sonic generations