There are gamers today who never played Sonic first time round. Never knew Sega at its triumphant, world-stomping best. Never saw a character shoot through a 2D world so fast it barely registered on the retinas. Gaming has changed so much. Everything is meant to be easily understood these days. God forbid a player should be thoroughly dazed and confused for a few seconds. Well, grab a controller and prepare yourself. Developer Sonic Team is in no mood to compromise with modern frailties.

It certainly doesn't take long for veterans to feel right at home. That cheesy '80s rawk soundtrack, the lovely ker-ching noise when you run through a line of rings, the loop-the-loops, the trampoline springs that send you hurtling into who knows where... Oh yes, this is classic stuff. Sonic Adventure - that bloated, flawed Dreamcast epic - added RPG elements in an attempt to transcend the boundaries of its platformer ancestry. But Heroes, simply, unapologetically, takes us right back to the beginning and then blasts us out over three dimensions.

But of course, this isn't just Sonic in 3D. The designers have added a modern tactical quirk. There are now four teams to choose from, each containing three characters: a fast one, a powerful one and a flying one. Hitting Circle or Triangle swaps your direct control between them, enabling you to exploit their differing abilities on the fly. It works like a squad-based shooter, but with dopey cars and camp rabbits replacing snipers and heavy infantry. Square activates your lead character's weapons, which can be combined with jump, or held for a few seconds to bring all your characters together, thereby opening different special moves. It's a varied, challenging setup, providing an array of options at every juncture. Do you go for Omega's spinning machine gun move, or the more accurate long-distance strike offered by Rouge's thunder shot? And how about the good old rolling attack, employed by speed characters such as Sonic?

Although there are places where the game suggests the best character types to use, most of the time it's up to you. This freedome of choice really makes the game. There's no right or wrong way to complete any of the fourteen stages. Not only do each of the teams have different mission objectives throughout (all entwined around Dr. Eggman's plot to unleash a weapon of terrible power on the world), but there are multiple ways to navigate each of the environments. Hidden passages, multi-layered runways - so much stuff you can't take it in first time round. In fact, when you start out, you just want to get from the beginning to the end in one piece. Sheer panic.

But then you begin to notice the complexity. From high points, you spot concealed platforms, lines of rings heading off in unchartered directions. On distant lands, you spot robots patrolling and boxes that may contain valuable objects. How do you get there? Ah, there's only one way to find out. Explore.

Most of you will want to go back, if only to look at the scenery again. Combining the brash, primary coloured comic-book land of classic Sonic with the pulsating surrealism of Super Monkey Ball, Heroes is like having Salvador Dali and Tex Avery taking it in turns to spray paint directly into your eyeballs. On the opening level, hugely reminiscent of the original Sonic The Hedgehog environments, you ping around gigantic cliff-faces and hurtle over narrow sea platforms while whales leap from the water. And on the brain-frazzling Casino level you spiral through an immense neon pleasure world where your character becomes the ball on a giant pinball table, ricocheting through translucent tubes suspended high above a night-time cityscape. This isn't gameplay, this is virtual tourism.

At times, there are the usual problems a 3D game can suffer: the camera can get lodged behind objects, and even when it's clear it tends to point in the direction you ought to be going, making it difficult to spot baddies coming up from the rear. There are also moments where you jump, Truman Show-like, out of the scenery and, for a second, glimpse only flat-shaded polys stretching off into a juddering digital eternity.

While we're bitching, we could say - with a considerably dose of irony - that Sonic is somewhat lagging behind his modern competitors. The likes of Ratchet & Clank and Jak And Daxter have taken the platform adventure into new, hugely ambitious territory. These are full-bodied adventures with varied objectives and fresh gameplay devices around every corner. Sonic Heroes offers multiple skills, multiple routes, but grafts them onto a formulaic platforming structure. Sub-quests? Puzzles? Characterisation? Forget it, pal.

And yet... And yet, Sonic Heroes is mightily compelling. No other game series manages to test your reflexes, to confuse, bewilder and beguile you like this one. And the combination of a tight structure with multiple paths and characters means that every time you play, you get something new out of the experience. You progress. You learn. Just remember, Heroes is an unavoidably nostalgic game. It doesn't really belong in this age, despite its many visual triumphs. It's like Disney releasing Fantasia in 2004 while the kids just want Finding Nemo. A work of something approaching genius, caught wildly out of time.

Graphics 80%
Great characters, vibrant environments.

Sound 70%
Fantastically silly music vs. camp voice acting.

Gameplay 80%
So fast it should be tested for steroids.

Lifespan 80%
Plenty of hidden stuff to keep you playing.

Overall 80%
A turbo-charged gem that refuses to go down the fashionable 'platform adventure' avenue, in favour of slick old-skool thrills.