Some things you can always rely on. Dr Robotnik will always be round, Green Hill Zone will always be strangely chequered and Sonic will always wear cheapo trainers with a "don't care" attitude. One thing you could never rely on was that Sonic, exalted in the days of the MegaDrive, could still perform in today's 3D world. Sonic Adventure 1 & 2 were full of speedy setpieces but felt more like tech demos for Dreamcast than enjoyable games.

Sonic Heroes still features lengthy on-rails sections, but is now far more interactive thanks to a new team-based dynamic. There are four teams to choose from, each with three distinct members. Team Sonic is the traditionalists choice, Team Rose is for newbies, Team Darl for experts, and the obscure Team Chaotix for masochists. Rather than controlling each team member, you pick the leader and the other two will follow you under adequate AI control.

Each team has three formations, depending on which blobby critter is under your control. Sonic, Amy, Dark and Espio can sprint faster and execute light dash attacks in Speed formation. Tails, Cream, Rouge and Charmy take their teams into Fly formation which lets you hover for a limited time and jump much higher. Power formation is the one you'll use most often, though. Knuckles, Big, E102 and Vector unleash baneful special attacks, taking out the baddest enemies as well as obstructions and brick walls.

With these powers in mind, Sonic Heroes plays a lot like a timed obstacle course. Knowing precisely when to change formation is the only way to achieve a good ranking. Being in Speed mode when there's a wall to traverse will cost you precious seconds. It's an original concept that gives Heroes the feel of a racing game rather than a platformer. Sadly, the awkward controls for changing formation mean you have to play tentatively when you really want to tear through.

Pressing the Y and B buttons cycles through the formations, often leading to confusion about which comes next. It would have been more intuitive to assign a separate button to each one. As it is, you'll either end up stopping and starting or fall to your death after a bad character switch. To make things worse, such a mistake will cost you all the rings and power-ups you've gained so far. Restart points are plentiful but to really achieve a high ranking you'll have to start from the beginning.

Practice makes perfect, and when you perfect your technique in Heroes you're rewarded with a hypnotic display of speed and graphical splendour. On-rails sections, such as the vertigo-inducing rollercoaster route to Eggman's hideout, are a visual and technical highlight, but they also lure you into a false sense of security. You'll die many, many times before you've learned the safe routes. Some of the devices that are meant to speed up your progress are another problem. Hoops, dash pads and cannons propel you forwards at great velocity, but it's often directly into the path of enemies.

The camera is mainly to blame for all this and is the biggest flaw. Aside from clipping right through the scenery, it fails to adjust to a high angle when you're flying. This makes it almost impossible to see where the ground is, or isn't.

Adjusting the view yourself is possible but extremely cumbersome when you're already under pressure. Light dash attacks often send you flying off ledges because the camera is facing in the wrong direction. Missed attacks like this are the most aggravating and downright unforgivable aspect of Heroes, especially because they're supposed to lock on automatically.

Every cheap death has a cumulative effect, slowly wearing down your enthusiasm for the bright, attractive characters and worlds. Sonic Heroes is a game you'll start out loving and end up being fatigued by after replaying levels over and over. It's still an awesome graphical showcase and a vast improvement over the last two Sonic adventures, but theres still much work to be done before the spiky one is back to his peak.

1. Terrifyingly fast!
2. Inventive levels
3. Impressive bosses

1. Losing power-ups after death
2. Being killed by a missed light dash
3. Team Chaotix

Power
A visual treat. Characters shine and the animation is full of charisma. Slight clipping issues.

Style
The whole teamwork, caring, sharing sentiment grates. Squeaky voiceovers should be discarded.

Immersion
You'll be hooked by the superb speed, but cheap deaths and the bad camera try your nerves.

Lifespan
Four teams equals many hours of play if you can stick with it. The games are a bit too similar though.

Summary
Beautiful but disappointing in terms of playability. Long lifespan, but you'll need plenty of stamina to clock it all.