In many ways The Saboteur is classic Pandemic. It's got a huge, 5.5km by 5.5km open world, with destructible environments and a mini-map on the bottom left hand corner of the screen. But in other ways it's like nothing we've ever seen from the sandbox genre. Firstly, it's a World War II game that's not a shooter. Secondly, the lead character is a race car-driving Irishman.

His name is Sean Devlin, as Irish a name as you could hope for. And, like most Irishmen, at least post 1918, he's not particularly political. This is a deliberate move on Pandemic's part, and a sensible one to boot. The Saboteur, according to lead designer Tom French, is more Indiana Jones than Saving Private Ryan. What he means is the Nazi's might be the bad guys, but at the end of the day their main purpose is to act like good cannon fodder and get shot.

Turning a blind eye to the politics seems an impossibility given the game's set in occupied France and stars a bloke who ends up fighting the Germans with sabotage, a tactic many in the French Resistance employed, but there you go. Indeed The Saboteur looks at the war through an interestingly stylised lens. The Saboteur is Pandemic's fantasy of what the war was. It's not intended to be GCSE Bitesize accurate. Devlin's in it for revenge. He's gunning for the Germans because they killed his mate while he was in town for a race, not because they threaten the entire world with genocide.

So, things like Zeppelins, The Saboteur's version of GTA's criminal-chasing helicopters, are in the game, despite the fact they were decommissioned by the time WWII came around. Some of the cars Devlin drives are entirely unrealistic, too. The Nazis never used shotguns, but for The Saboteur that's fine. Other entirely fictional weapons will be available from the Terror Squad, the black market faction that will sell Devlin tools of destruction as unlikely as flame throwers.

Sean Devlin is The Saboteur's Altair

None of that, however, is quite as interesting as The Saboteur's colour-based tug of war territory mechanic. Nazi-held areas are coloured black and white, with areas of interest highlighted in red, giving proceedings a lovely WWII meets Sin City look. As a result, much of the French countryside is in colour, save for the odd barrack or road block, so when you drive outside the city The Saboteur almost looks lush. On the streets of Paris, however, things are different. It's almost entirely drenched in black and white. Paris, after all, is where the occupation was felt most.

Devlin can make a difference by dipping his toes in "Fightback Zones" - pockets of fighting between the French Resistance and the Nazis. These AI-governed battles happen with or without you, so you can decide to step in and help your French mates out if you want, or you can turn a blind eye and carry on with the story-based missions. But getting your hands dirty may be of benefit. Spend contraband, the game's currency, on improved weapons for the Resistance and they'll stand more of a chance in these Fightback Zones. When an area has been cleansed of the Nazi occupation, colour will magically rid the black and white from the world, making it much easier for you to explore. And, when you're on the Resistance's good side, you'll find them useful allies when escaping a Nazi pursuit.

While The Saboteur contains classic sandbox mechanics the likes of which we've seen in open world games before, including the developer's disappointing Mercenaries 2, Pandemic has spent a great deal of effort implementing the kind of missions we're not used to seeing in the genre. French shows one off: a train mission set two thirds of the way through the game. Devlin is driving towards his destination with the sexy upper-class Brit Skylar in the passenger seat. They engage in ridiculous sexy small talk - "I just like to see you sweat," she says. It's a revealing line. Up to this hands-on, we'd thought The Saboteur a refreshingly mature take on the open world genre, but it's dialogue like this, the recent release of screenshots showing prostitutes leaning on brothel walls with their tits out (yes, you can visit brothels in The Saboteur - indeed one is your base of operations), and Sean doing his trouser zipper up after leaving a brothel, that paint the game with a more adolescent brush. One of our key concerns with the game is that, for all the good work Pandemic is doing with the WWII/French resistance premise and plot, it'll ultimately be undone by a desperate attempt to get horny teenagers interested in it.

Yes, The Saboteur features nudity.

That's not Devlin's problem, though. He's too busy worrying about his mission, one that demands he help a scientist fake his death so he can escape France without the Germans in hot pursuit. To do this, he's going to sabotage a bridge, one that the train carrying the scientist is due to cross any time now. So, the first part of the mission involves Devlin planting explosives on hard to reach struts. Now, in true open world style, there are a number of ways he can do this. He can go in all guns blazing - a tactic that will result in death more often than not, French says. Or, he can go in all sneaky like, knocking out a Nazi and donning his garb as a disguise. This is how we do it.

Dressing yourself as a German isn't a get out of jail free card, however. All enemies have a perception range in which they'll spot suspicious behaviour. That includes running about and shooting stuff. So, Devlin needs to play nice, walking rather than running, gun holstered rather than aimed forward. Here, French shows off Devlin's Altair-esque free climbing skills, which enable him to reach the objective markers and plant the explosives. Devlin climbs with somewhat incredible ease, almost like a monkey with super strength - again, it's a deliberate move. Pandemic wont be a slave to reality. "If it looks like you can climb it," French says, "you can climb it".

Despite his disguise and skilled stealth, it's not long before the Nazis spot Devlin doing something untoward and his cover is blown. This gives French the perfect opportunity to show off The Saboteur's cover system, something "every game has to have these days". You'll be able to snap to cover with a button press, but simply moving towards cover will trigger the correct animation. At this point French describes Devlin as "Steve McQueen, John McClane and Indiana Jones all rolled into one". That's one hell of a combination.

With the charges planted, it's time to jump on the train. Here, The Saboteur cleverly forgets it's an open world sandbox and transforms into the kind of scripted, set piece-driven experience the train mission is designed to be. Devlin is hopping from cover to cover as he fights his way to the front of the train. Turrets are conveniently placed on the car roofs - another nod to fun over realism. When used, it's absolute carnage. You're even able to take down Nazi towers set into the French countryside as you whizz by them, something that may be in your best interests, says French. Certain structures in the game are persistent. Destroy them and they're gone forever. These "targets of opportunity" might be search light towers, machine gun emplacements or anti-air guns. Softening them up for later missions will be a tactic skilled saboteurs will want to employ.

With a cool art style, interesting open world mechanics and an Irish lead, The Saboteur could be a surprise hit.

After killing scores of Germans, Devlin makes it into the scientist's cabin. Here we see that, despite everything else being black and white, Sean's eyes burn in bright emerald green. But the scientist is not who he seems to be. He's a Nazi, and a punch up ensues between them. Red blood splatters on the screen - a Sin City moment. The real scientist is tied up in a secret compartment. He throws him out of the speeding train before leaping out himself. The train moves over the bridge. It explodes and sinks into the chasm below. The mission is over, the Indiana Jones, Die Hard, The Great Escape moment is finished, colour bleeds out into the world and birds start chirping.

French promises 20 to 25 hours of main campaign gameplay and five to ten hours worth of side missions for those who want it. As with all great open world games, however, it's the surprises, the stuff simply stumbled upon while out exploring, or the special moments that occur as a result of messing about with the game world, that's most important. We love sandbox games not for what developers expect us to do inside them, but for what the developers don't expect us to do inside them. What scope The Saboteur has for such malarkey remains to be seen.

What our hands-on has revealed, however, is that The Saboteur is an altogether less serious game than its French Resistance/WWII premise suggests. The action is all about sandbox mayhem, as it was in Mercenaries before it, and nothing, not even historical accuracy, is going to get in the way of that design philosophy. We already reckon The Saboteur's setting, art design and mechanics are a mile more interesting than Mercenaries 2. Fingers crossed, then, that the tits and brothels don't get in the way.

The Saboteur is due out for PC, PS3 and Xbox 360 on December 4.