As good as Crash Bandicoot used to be, and as much as he zipped around the screen like a whirling orange dervish, his series was still essentially a side-scrolling platformer. Sure, it was all done in polygons rather than pixels, but you worked your way through levels by following what were essentially rails. But boy, how things have changed.

Crash has gone free-roaming and along for the ride is his nemesis, Dr Cortex. The reasoning behind this bizarre partnership is long, but centres around the invasion of Crash's planet by two extra-terrestrial parrots. They eat fast food and they like obliterating the living, and when Cortex goes head to head with them to stop the attacks, they suck his brains out. Cue an unlikely partnership with Crash, and a quest to save the world.

Great thought has been given to this new dimension of gameplay, and the pairing of Crash and Cortex has had every last drop of invention squeezed from it. If you're not using Cortex as a hammer to smash obstacles, you're fighting with him. In a flurry of fists and feet, the two of you roll around in the path of danger and you have to steer the brawl from one point to another like some kind of organic Marble Madness. Then there are times when he'll be stumbling around with a beehive lodged on his head and you have to demolish traps before he stumbles into them.

There are moments when Crash goes it alone though, namely when traversing the nastier parts of a level, such as stealthily moving through a village of insane spear-chuckers. The last thing you need here is a mad professor screeching around with brains dripping from his ears.

Thankfully Crash loses nothing making the transition from rails to sprawling platformer. If anything, the humour and story have been upped considerably. Very few games can manage genuine laughs, but this is one of them, and it's all the better for it. The relationship between Crash and Cortex is reminiscent of classic Hollywood comedy duos and this, combined with the open-ended mission structure, makes Crash Twinsanity something of a doozy.

There are moments of pure frustration thrown into the pot as well, though. If a level isn't frying your eyes out, you've got to be careful of your step. Some perspectives when block-jumping can be pretty deceptive, forcing you to repeatedly shift the camera to a top-down view so you can see just how far you need to leap. Then there are the levels themselves. We saw glimmering jewels way below us and decided to hurtle down the mountain to fetch them. Only when we reached the bottom did we realise we'd just inadvertently returned to the beginning of the level, and had to replay the whole thing. It allowed us to reap another bunch of wumpa fruit, but it took us an hour. While wumpa fruit mean extra lives if collected in abundance, a measly extra life really isn't compensation enough for the hassle.

The new Cortex weapon (for that's all he really is) adds great variety to play. And whether you're dodging the vicious laser eyes of the giant Mecha-Bandicoot, or being blasted with the vice-versa reverser device from the tenth dimension, you'll forget the orange marsupial ever had dubious dalliances, such as that whole karting craze a few years back. It's not in the same league as the infamous plumber, and the partner/weapon gimmick isn't new (Whiplash did it before), but it's a sturdy exercise in comic gaming. We'll even forgive the fact it's ginger.

1. Open-range missions give a new depth to the series, and releasing it from the scrolling gameplay gives Crash legs for years to come.
2. The use of Cortex as a weapon may have been done before, but the range with which you get to use him has us taking our hats off.
3. Levels can become very frustrating, especially when the perception of depth gets muddled and you're left taking leaps of faith.
4. In-jokes and comedy lift Twinsanity well above your average platformer. The script is so sharp you could cut yourself.

1. Why create levels that could accidentally see you right back at the beginning? How annoying. We don't like!

A nice, thick wedge of mayhem and quality gaming, but nothing ground-breaking. Crash fans will adore it.