Rockstar's behemoth Grand Theft Auto IV crashed on to the scene in April last year, and has managed to amaze and enthral gamers ever since.

In fact, we voted it our Game of the Year 2008, and with its immersive sandbox environment created on an unprecedented scale it's not hard to see why.

Since the release, Rockstar haven't exactly been resting on their laurels. Late last year we were treated to an updated PC version, which increased the multiplayer limit to 32, and added a host of graphics options along with a nifty video editing suite. 2009 seems set to be the year of DLC, and to kick this off we have the Xbox 360 exclusive The Lost And Damned.

 
GTA IV: The Lost And Damned

Downloadable content typically consists of relatively small software packages that either modify or in some way enhance an existing title. With console DLC still very much in its infancy, it's fairly unusual to get massive updates to existing titles, however in the case of The Lost And Damned we can confidently state that there is a large slice of Liberty City on offer, with new characters, missions and weapons that significantly add to the base game.

We sat down with Rockstar in Auckland today, and were fortunate enough to play through several missions and have a talk about the direction taken with this DLC. The Lost And Damned follows the story of Johnny, an otherwise minor character in Niko's original Grand Theft Auto IV story. Johnny is second in charge of The Lost biker gang - in fact, you may remember him assisting Playboy and Niko steal some heroin for Elizabeta in "Blow Your Cover", which is a mission that you can now replay from his perspective, providing a whole new twist to a familiar story.

Rockstar were quick to point out that where Grand Theft Auto IV was more of a solitary game, full of explanations and gradual introductions to the vast game world, The Lost And Damned assumes you're already completely familiar with Liberty City. Johnny's phone is already full of contacts, and your can travel wherever you like, so instead of telling a story of one man's struggle to succeed against overwhelming odds the focus here is brotherhood, co-operation and uninhibited gang warfare.

 
GTA IV: The Lost And Damned

We started by witnessing an early mission in which a truce between The Lost and their arch-rivals, Angels of Death, is broken. After an execution-style killing on the street, The Lost set off in pursuit of a pack of Angels to prevent them from informing the rest of their chapter that a state of war now exists between the two gangs. Your task here is to gun down as many as you can from the seat of your bike, and although our Rockstar representative made this look pretty easy, it's clear that the difficulty level, even at such an early stage, is designed to mirror the skill level of someone who has previously spent a fair bit of time getting Niko out of trouble.

An interesting new concept featured with this DLC is an almost RPG-style allocation of points between yourself and your gang members after the successful completion of each mission. Those who ride with you gain points that allow them to perform at a higher level, which encourages you to look after them as much as they look after you. We're still a bit sketchy on the details, and exactly what sort of performance increases will be seen, but it clearly all related back to the brotherhood theme so prevalent throughout the new missions.

Speaking of which, when you're riding in a group with your gang, your gang insignia is projected just behind the leaders bike on the surface of the road. If you stay within this insignia, you'll receive a small health boost and the ability to banter with your gang associates, further increasing your standing within the group.

 
GTA IV: The Lost And Damned

It's not only small changes such as this that have occupied Rockstar over the previous few months. One major addition is the railed-in shooter experience, a feature lacking in the base game. In one mission we witnessed, Johnny is tasked with shooting cops from the back of a bike being piloted by an associate, and as we had to repeat this several times we noticed that the dynamic damage taken by the vehicles caused different crash sequences each time. For example, we were certain that after shooting a helicopter out of the sky and watching it fall directly in front of a pursuing cop (which resulted in a satisfying explosion) that this must be a scripted sequence, however upon repeating the mission it crashed in an entirely different location, leaving us to figure out a new way to dispatch our pursuers.

There's plenty of new weapons too - from grenade launchers to auto pistols and shotguns, although possibly the most beneficial addition is a new checkpoint system within missions. Any mission that switches to a cut-scene during an action sequence will allow you to resume the mission from that point should you fail. A constant gripe with Grand Theft Auto IV was the tedium associated with backtracking, finding more armour and ammo, and simply gearing up to retry a mission. The Lost And Damned is tailored towards fast action and this checkpoint system reflects that.

 
GTA IV: The Lost And Damned

The Lost And Damned is the first of two planned expansions, and it's clear that Rockstar intend the Grand Theft Auto IV story to continue within each episode. We've been promised that you'll be able to hear not only a stack more metal-orientated music on the radio, but you might just hear about a taxi depot catching fire too, and you'll certainly be seeing more environmental objects. In fact, more of everything really.

We'll bring you a full review when the game is released on February 17th, although there's no doubt in our mind that this will be a must-have for 360 owners who have already enjoyed Grand Theft Auto IV. Last time we checked, there were an awful lot of them.