Prototype

If Mirror's Edge is the Project Gotham Racing of action-adventure games, all precision timing and meticulous button-pressing, Prototype is Burnout. It doesn't matter if you're going so fast you end up swerving a bit or scraping up against something. The best part is racing up the sides of those skyscrapers. There's no fear of suddenly plummeting back down at any given moment because you've run out of steam, or hit a curved surface, or come up against the wrong kind of window. You just keep on running and next thing you know you're on the roof, surveying the city from the best vantage point possible.

So how do you get down again? Naturally, there are a range of options available here too. You can just jump, with no fear of Alex's super-human frame suffering any damage on impact. With a single button-press you can turn that jump into an elbow drop, taking out any civilian, soldier, mutant or tank below. You can spread your arms and glide. Or, if there's a helicopter in the vicinity, you can leap onto it, sling the pilot out of the cockpit and start playing with its heat-seeking missiles.

You can also hijack helicopters if you're on the ground. Alex can jump extremely high, depending on how long you hold down the button to charge it up. It's great fun to work out just how high you can go, bouncing up and down like you're on a concrete trampoline, then grab a helicopter in mid-air. Or if you're feeling lazy, you can turn your arm into a grappling hook, pluck one out of the sky and winch it in towards you.

Alex's arm can also be transformed into a giant blade, a super-resilient shield, a bouquet of razor-sharp spikes and a huge hammer for punching tanks, amongst other things. Then there are his other powers, like thermal vision, the ability to generate his own suit of armour and super-strength that allows him to pick up and throw vehicles. But the most intriguing ability is what Radical's referring to as "consume and become". This is Alex's power to ingest people, as illustrated by a nicely gory animation, and acquire their physical appearance, skills and memories. A bit like Kirby.

So Alex might consume and become a soldier then call in an air strike or sneak into a military base, that sort of thing. But Fuller shows us a less obvious example of how this power can be used. Having consumed a Black Watch operative, he raises an arm, points a finger and accuses another soldier of being Alex Mercer in disguise - "That's him, right there!" The soldier pleads innocence but within seconds all his comrades have turned on him. While they're busy blasting him to bits, the real Alex walks calmly away in the opposite direction.

Unfortunately, we can't try this out for ourselves - it features in the code Fuller is showing off to us, but not in the demo we're allowed to play. Nor does the demo include the mechanism for switching between powers. Nor are we allowed to experiment with upgrading his abilities.

It's these elements which will determine just how good a game Prototype is. Yes, running up skyscrapers, punching tanks and so on is brilliant, but the novelty will wear off, and the more fundamental structures of the game will be what matters. If switching between your hammer and your grappling hook isn't seamless and intuitive, frustration will set in. If poor AI means enemies are thick anyway, there won't be any satisfaction in tricking them.

Plus, without having been allowed to play with the upgrade system, it's impossible to judge how much control over you have over the development of Alex's powers. Will you be forced to choose between speed and strength, for example? Will you have to spend hours fiddling about with upgrade menus and Evolution points? Just how many side-quests will you have to complete before Alex is as powerful as he is in the demo?

At least what we've seen so far of Prototype is promising enough to make these questions worth asking. And the answers are likely to be more interesting than who unleashed the mysterious virus, who Alex Mercer really is, why he only owns jumpers with hoods attached etc. Let's just hope they're the right ones.