CRUNCH! The rim comes flying off of the back wheel of our armoured security van, burst by an eagle-eyed copper aiming from a pursuing cop car. We battle to control the battered van as it swerves across the Liberty City highway, with twenty police cars burning metal behind us, eager to ram us into the nearest lamppost.

The entire Liberty City SWAT team is on our case, after we managed to snatch a notorious criminal boss from their custody at the Francis International Airport. But it's only a short stretch across the city to sweet, sweet freedom, and the rendezvous point is in site...

Suddenly it looks like it's all over; two loaded-to-the-teeth attack choppers emerge above the sprawling concrete horizon, miniguns aimed and poised to turn us into a flaming chunk of twisted metal. Our task to escape with the NPC convict looks almost hopeless, until we realise that not all the helicopters in the sky are being flown by the police...

As the first police chopper falls flaming towards the road, the second player - with a third gunning from the back of the 'copter - lays down covering fire on the police convoy laying chase behind our van.

The fourth player is laying down covering fire from the passenger seat next to us. This is GTA IV multiplayer. And it's bloody brilliant.

Liberated City
Just like the horribly overlooked Vice City Stories PSP multiplayer modes, GTA IV has fifteen different online games lined up, ranging from co-op shootouts with the police to mental 16-player shootouts across play areas the size of Hackney.

You could forgive the series' previous mammoth single-player games for lacking multiplayer action, but now GTA IV's gone and delivered both.

Starting off in the lobby menu, you can access the character customisation menu by pressing Y. From here you can switch between different player heads, torsos, legs, hats and glasses, and choose the sex of your character.

From the start there are only three or four different selections to choose for each option, but we're told more options unlock as you progress through the single-player campaign.

Gangster-ed up and ready to go, we hop straight into our first 16-player Deathmatch game, on a small cemetery island just off the coast.

Instantly, the GTA IV formula feels perfect for online carnage; players sprawl across the island, picking up guns and armour and staging their own one-on-one (and sometimes one-on-one-on-one) shootouts behind tomb stones and parked cars. Occasionally the odd brave soul will come tearing in from the street, gunning from the driver's seat of a saloon, only to get gunned down and used as cover.

Thanks to GTA IV's excellent cover mechanic and massively refined aiming controls, it's all a much more strategic - and less random - Deathmatch experience than Vice City Stories. In case you missed it, aiming and shooting has been handled in quite a unique manner in GTA number four; holding down the left trigger locks on to a target, and you can cycle through targets using the right stick.

From here you can shoot at an enemy's chest, limbs or head - but it's not totally automatic. The cursor is locked on to the centre of a target's chest, and from there you can move your aim with the right stick inside a small circle radius around the target - so there's still some skill. Free aim is also instantly accessible by holding the trigger half-way in, which works well.

Cover plays a prominent role in coming out on top, but this isn't Gears of War either. Aiming and where you hit your target also feels incredibly important to winning a shootout. Headshots always equal a one-hit kill, whereas body shots take a whole lot longer.

Of course, this all goes out the window when you kick off a rocket launchers-only match, when cars (and people) get flung kilometres at a time from the brunt of the carnage. This gave us a chance to try out another of GTA IV's new and tactically-pleasing features - the radar, which lets you see other players' locations at all times.

It works really well as Liberty City is a hell of a lot bigger than your average Call of Duty map. Even these slimmed down multiplayer chunks can take ten minutes to cross. So it's nice to be able to see where the carnage is going on via the blips on the radar.

This keeps the combat central and injects even more strategy into the sandbox shooting formula. If you crouch and creep around you'll disappear from your enemies' radar sights, allowing you to sneak behind cheeky rocket launcher campers and stab them in the back. We don't think we've ever cursed so much on Xbox Live.

Law in your own hands
Liberty City Deathmatch is awesome, but our favourite of GTA IV's multiplayer modes are easily the team-based games such as Hangman's Noose and Team Mafiya Work. Just in our day's gaming session, these have provided some of the most memorable GTA moments we've ever had, and some of the most enjoyable online action of the year as well.

Take, for example, a high-speed chase with an armoured van - driven by two real players - with our mate gunning from the passenger seat and us at the wheel. Speeding and smashing through busy traffic we're gunning like mad men at the van, but its armour's simply too thick to penetrate.

"Take out the tyres!" my comrade yells over his Xbox Live headset, just as we swerve to miss a grenade the players in front have dropped in our path.

It's as intense and fast-paced as any chase we've ever had in GTA's single-player, and the heat turns up a notch when the target player van swerves around a corner only to topple on its side, resulting in an on-foot shoot out on the street. Just like this, GTA IV multiplayer lets you play out your favourite GTA solo experiences with real people, which is simply brilliant.

This is exploited to the max in eight-player team mode Cops 'n Crooks, which pitches four coppers against yes, you guessed it, four crooks in a round-based setup. Cop players get the advantage straight away, starting off in a police car armed to the teeth with SMGs and grenades.

The crooks, meanwhile, start off on foot with one randomly selected VIP player who needs to be escorted to an evac zone at the other side of the city. The cops have to kill him. With the blues 'n twos blaring in the distance, the chase is on.

Playing on the cop team is a game of cat and mouse, thanks to the other little advantage they have in being able to see where the crook team is at any given time on radar (the crooks are totally radar-blind).

In our play session the law instantly then became all about stealth; turning off the sirens, sticking your best driver behind the wheel and coming at the enemy players from all angles.

The cops can also see which player is the VIP on their radar, so the other crooks serve merely as a nuisance in the inevitable high-speed city chase that ensures - just like the one we mentioned above.

The crooks in our session were far more enjoyable to play as (which isn't a problem because the teams are swapped after each round). The satisfaction of shooting out the tyres of a pursuing four-player cop car, and then watching it smack into the side of a bus stop as you speed off towards freedom, cannot and hasn't been matched in any game of this type we've played.

Another incredible, typically GTA moment happened when in the passenger seat of a player-driven Crook vehicle. My driving buddy escaped the chasing player's cops by nailing a hidden jump ramp, sending us flying over several walls and the Liberty City highway.

The two pursuing player cops scuffed it, span through the sky and landed upside down in a pile of sparks as we sped off to freedom. Just like in the movies.

Midnight Club
Next we loaded up GTA Race, a frantic, incident-filled competition across one of Liberty City's many islands. At first glance it's a simple, Midnight Club-style race with waypoints pin-pointing the way ahead. But thanks to a number of subtle gameplay nuances it's a lot more enjoyable than we expected.

Weapons, for example, are laid out across the road Mario Kart-style, and you can only carry one at a time. This has you constantly choosing between Uzis to shoot out the tyres of the bloke in front, or grenades to decimate the guys behind you.

Realism is a much stronger theme in GTA IV's driving than before. It's much more difficult to simply right-angle around a corner at speed, and if you don't want to be sent into the side of a building by a bump in the road, you have to slow down. Damage as well makes a massive difference to your handling, and flat tyres resulted in us having to bail out more than once.

From our time, it felt a lot more about learning the streets than driving like a souped-up Saxo as well; in nearly every game we played the first corner resulted in a massive pile-up as everyone scrambled for the lead. Slowing down to hold back helped us avoid the chaos every time, even if it is a really cheeky tactic.

Thankfully though, this being GTA, taking a wrong turn or crashing into the scenery isn't an automatic game over. Thanks to the inevitable gun-crash-'n-explosion carnage up front, catching up with the pack isn't a difficult task. Especially because you can bail out of your starting car (which every player begins with) and hop on a bike or sports car laying around in the street.

Talking of bikes, one awesome GTA Race scenario had us weaving in an out of the Francis International Airport terminal on two-wheelers. Underneath moving 737s, around baggage carts and down the runway in high-speed SMG-blasting chaos; it's one of the few game modes that actually had us chirping, "Let's do that again!"

Co-op carnage
By far the most impressive section of our play date, in terms of sheer scale and spectacle at least, was the one mentioned in the opening of this article.

Hangman's Noose is a no-holds-barred, co-operative battle with Liberty City's entire police force. This is the real meat of GTA IV's co-op, which teams you up with three mates to protect NPC gangster lord Kenny Petrovic as hell breaks loose and the SWAT teams descend. Make it across the city to the rendezvous point with Kenny alive - and your three teammates - and you've won the game. Simple as that.

The opening section has you battling against the Liberty City police at Francis International Airport, which is just as impressive to have a shoot-out in as it is to drive through in GTA Race. Massive jumbo jets move around as you dash to and from baggage holds, and the scale of the airport buildings themselves is far more intimidating that anything in San Andreas.

Extra cops scream onto the scene in armoured cars from all sides, and can easily catch you off guard if you're too dazzled by the pretty planes. Kenny is held up inside his private plane at the rear of the terminal, and will refuse to come out until you've taken out all the police gunmen first.

With four guys covering the side of Kenny's private plane, the AI coppers admittedly don't provide much challenge (although you can turn off stuff like auto-aim in the host options). But Hangman's Noose is all about the spectacle; getting Kenny and a second player in an armed van and then sending off your mates to cover in a parked up attack chopper.

We always wondered where the limits - the invisible walls - were in GTA IV's gorgeous game world. But piloting a chopper over the top of the city centre, with the blinking lights of skyscrapers laid out beneath us, a mate in the back firing off rifle shots and the other two players outrunning 20 police cars on the road below, it didn't seem to matter.

The view from the back of the chopper is stunning - even if your puny rifle shots are useless compared to the pilot's beefy minigun.

Just like Crackdown before it, the sheer scale of the carnage you can cause with other players running together in Rockstar's sandbox is very impressive. Screaming our armoured van across the highway with Kenny in the driver's seat, the second player fired off pot-shots from the rear, nailing a cop car's front tyre and sending it tumbling across the tarmac, Bad Boys-style. The resulting copper pile-up isn't quite as satisfying as sending a player cop car hurtling into a lamp post, but it looks brilliant.

If you're driving skills are up to task it isn't much of a problem keeping the convoy of police cars behind you at bay. Especially if you've got a healthy stash of grenades; pressing the right trigger drops a primed one out the window, guaranteeing that anyone within a few metres behind you is going to need a new MOT.

With the police taken care of, us and our buddies finally reached the escape chopper on the other side of town - and it's game over. Hangman's Noose is definitely the most visual of GTA IV's multiplayer offerings, though because of its linearity it probably won't last as long as the others. It was a brilliant single ride, though.

Not even trying
Rockstar didn't really have to try too hard to pull of GTA IV's multiplayer mode. It has, after all, all been about the city and the playground that the player makes their own fun in.

Deathmatch and Team Deathmatch thus feel like really obvious and immediately effective setups, while stuff like Cops 'N Crooks throws a genius premise into the toybox.

Other modes, such as Hangman's Noose and GTA Race are far more linear, and we reckon their shelf life will ultimately depend on exactly how much depth Rockstar's packed into each scenario - something we'll find out when we get the chance to have a more extensive play session.

Chasing down a car full of players, firing shots from the back of a mate's chopper and racing bikes across the airport are all standout moments in GTA IV multiplayer, and for most people it's these that've made the series worth checking out in the first place. So even as a one off, playing with friends looks like a terrific counterpart to Rockstar's already massive single-player campaign. More soon.