As far as game icons go, you don't get much bigger than Sonic. For all the talk of "next generation" gaming, photo realistic graphics, hyper real facial animations and movie quality voice acting, if you stop your average punter on the street and ask him or her to name three video game characters, one of them is guaranteed to be Sonic the Hedgehog. And Sega, which is fully aware of the continuing popularity of its blue-skinned hero, is still happy to pump out game after game featuring the quick-witted little speedster over 15 years after he first exploded onto the scene.

This publishing policy has had varying success over the years. When I say success, I mean in critical terms of course, because it's clear that Sonic games still fly off the shelves faster than the spiky one himself could ever hope to go, irrespective of whether they're a pile of steaming cow dung or a worthy addition to the Sonic the Hedgehog game compendium.

So, is the PSP exclusive Sonic Rivals 2 a worthy addition to the Sonic the Hedgehog game compendium, or is it a pile of steaming cow dung? Read on.

First thing to get out of the way is that Sonic Rivals 2, the sequel to Sonic Rivals (duh), is not an adventure game, so it immediately isn't a pile of steaming cow dung. Far from it in fact. The gameplay, as owners of the first Sonic Rivals game will know, concentrates on beating your opponent to the finish line of levels that play out much like the classics we know and love from the original Sonic games. The difference is that both of you are on screen at once, you can disrupt each other's progress with special abilities and power ups and the emphasis is on speed over exploration.

This is a good thing. Sonic is all about speed, and so is Rivals 2. It's a more refined effort than the original - the levels are now less about trial and error and more about skill, and the game is certainly more polished, with fancy 3D sections where the level will move in and out at different angles, and spectacular loops and corkscrews explode on screen as the action whizzes by at 100 mph.

There's also decent variation between the characters too. What seems like every character ever conceived in a Sonic game returns and each has their own Signature Move, powered up by collecting rings or defeating enemies. So Sonic has Sonic Boom, which makes him go even faster, Tails has Tail Copter, which lets him fly over large distances and Knuckles has the Knuckle Slam, a close range stun attack. All the other characters, Rouge, Shadow the Hedgehog, Metal Sonic, Silver the Hedgehog and Espio have signature moves too. The signature moves vary in terms of usefulness. They don't have quite the "oomph" factor you might have wanted, but some of them do help turn the tide of the race. Perhaps predictably, Sonic's Sonic Boom is the best signature move. This is a race to the finishing line after all, and a hefty speed burst really helps you either catch up or increase your lead.

What I don't like about Rivals 2 is the one on one battles, which are so boring they could easily be replaced by a virtual boiling kettle and I'd be more entertained. Think the ancient Super Mario Bros. mini games, where you have to climb levels and avoid Koopas. It's like that except with the odd power up and fiddly controls. One of the battle modes, Knockout, sees each player start with three rings. The winner is the first to hit their opponent after knocking all of their rings out of them. Woo.

The story, really only filler content, will only be of interest to younger gamers and plays out like an episode of the cartoon series, with suitably cringe-worthy voice acting and a sound track all Sega fans have heard a million times before. The Chao have gone missing and Sonic and Tails investigate. It's all Eggman's fault of course, and it's up to you to sort the mess out. The story mode itself is good fun, and will keep you entertained for about five hours or so depending on skill level. You battle through three acts and a boss across familiar zones, Blue Coast, Sunset Forest, that sort of thing, with a character of your choice, each with their own storyline, which adds replayability.

Battle Mode is boring, but racing is great.

You've then got the option of going old school with the free play mode, which allows you to speed through the game's levels on your own in classic Sonic fashion. Again, because the game hasn't strayed too far from the original Sonic the Hedgehog gameplay, this isn't too bad either. Add to this tonnes of unlockables, including art from the old Sonic games and character costumes, and you've got a hefty single-player game to pass the time on the lonely commute home.

What is a bit of a let down is the multiplayer. Here you've got six variations of the previously mentioned battle mode, from Knockout to Capture the Chao and King of the Hill. The problem isn't the quality of the battle modes (although they vary in the entertainment stakes). The problem is that you'll only get the most out of them if you've got a mate who's also got the game. Playing wirelessly with only one copy of the game is pretty rubbish. You can only fight in Battle Mode, which I've already said is boring. All I want to do is race. That's the best thing about Rivals 2 by a country mile.

Despite the niggles the main thing to say about Rivals 2 is that it's great fun. And fun, lest we forget, is what it's all about. The whoring of Sonic the Hedgehog continues of course, but the Sonic Rivals series continues to do its best to stem the flow of blue-skinned cow dung.