Red Dead Redemption

It's a classic Rockstar moment. The nocturnal calm is shattered by the shrieks of a prostitute bursting out of a saloon as a man chases her down and assaults her in the street. I move swiftly to her aid but, still acquainting myself with the controls, succeed only in kicking her in the face as she writhes helplessly on the ground.

The man flees back inside as the girl scrambles to her feet and away. I give chase to the attacker, drawing a rifle as he cowers behind the bar blind-firing. A moment later I have him clean in my sights by the open backdoor and unload a round. Which sails past his torso, through the door, over the street and into the stomach of a girl 20 yards away, who drops to her knees with a blood-curdling scream. The same girl I'd been trying to save. There are belly laughs and there are belly laughs.

It's one of those sudden, unexpected climaxes of bloody action, tinged with darkly comic absurdity, that have become a trademark of Rockstar's openworld exploits. Pigeonholing Red Dead Redemption as 'GTA Wild West' is a seductively neat but ultimately lazy option, handy for journalists seeking to articulate the concept with a tabloid flourish, but one that undermines what is - if not in essential mechanics and structure - in tone, ambition, scope and potential very much its own beast.

The heritage and influence of Grand Theft Auto are important because through its all-conquering series Rockstar has created then refined a genre, while becoming a master at realising the dramatic potential of the medium.

Red Dead Redemption is, the publisher often states, the fulfilment of a dream that began with picking up the half-finished Revolver from Capcom, acquiring the developer, Angel Studios, and renaming it Rockstar San Diego - to create the great videogame western.

Hands-off demos have impressed the leather chaps off us so far, but earlier this week Rockstar invited us over to its London HQ to climb into the saddle ourselves.

First, though, a Rockstar rep gives us an updated snapshot of the project and a taste of what's in store. We start on a map screen, slowly zooming out for effect to reveal the full scale of the gameworld. The huge expanse of land is bisected by a river, with the Americas to the north and Mexico to the south, split into three distinct territories: New Austin, West Elizabeth and Nuevo Paraiso.

Redemption is the largest openworld game Rockstar has made. Size in itself is not an unalloyed good, as those overwhelmed by the vast San Andreas would testify; but an unexplored, unknown wilderness is the point here. Set at the turn of the 20th century, the tension between the lawless old west and the rapid expansion of government and the rule of law is central both on the narrative and the character of protagonist John Marston, torn between his own outlaw past and second-chance family life.

The proto-FBI Justice Department demands Marston help them bring to justice his former gang. His family threatened with execution, he's left with little option but to comply, loyal only to himself as he works with whomever and whatever it takes to protect his wife and child.

We're walked initially through a mission in Nuevo Paradiso, where Marston has sided with the Mexican Army to attack and expel rebels from their stronghold. It's a frenetic firefight that snakes up a rock formation and towards the enemy base on a cliff edge. Rocks and the ruins of razed masonry provide cover as Marston and the army press forward against dozens of rebels.

Cover-and-fire is straight out of the GTA playbook, enhanced by Dead Eye - the system used in Red Dead Revolver - which slows down time allowing Marston to pick out multiple targets and unleash a flurry of fire. But with around 10 rebels moving in for the kill, the rep hurls a few molotovs which flame panic and pain all around.

On approach to the stronghold, Marston turns sniper to nail the last few defenders before the army storms the building and eliminates the remaining rebels, springing a cut-scene. The rep lays down the controller to talk through more features, which allows the game to run through a day-and-night cycle as Marston broods by a cliff edge.

The rich, deep reds of the rocks and mustard-yellow plains are bathed in dimming light as the sun sets behind the mountains on the horizon. The sky darkens to reveal a starry blanket above as background music fades to reveal the incessant chirp of crickets. Oh, and the wild whinnying of a horse which inexplicably falls backwards off the cliff. A bug, I presume, rather than black humour in this instance.

It may not be as awe-inspiringly gorgeous as the vistas of Uncharted 2, but there's a crucial difference. Everything you see - and the view stretches for miles around - you can visit. That, in essence, is the wide-eyed promise of Red Dead Redemption: the great, unconquered frontier that lies before you.

A word on the music. Inspired by the great big screen westerns, the Redemption score's blend of portentous pedal notes, snarling muted trumpets, seedy basslines and wistful harmonica riffs feels entirely appropriate and dynamically adapts to the action. Brilliantly judged licensed soundtracks are a staple of the GTA series; here the soundtrack is entirely original (and Rockstar coyly teases that an announcement about the composer will come).

Hands-on time! In the small town of Armadillo, Marston persuades the Sheriff to help him track down a former associate. As one of the early encounters in the game this is in essence a training mission guiding you through combat controls. First, a horseback ride to the troublemaker's hideout.

You can ride any horse in the game with a press of the Y button (we're playing on Xbox 360); A is used to trot or gallop. Mission transits perform a similar function to car journeys in Grand Theft Auto, allowing the story to develop through dialogue (which, again like GTA, has multiple variations if you repeat a mission). In these situations, holding the A button puts the horse in, curiously, 'cruise control', matching your pace with the other rider so you only need worry about steering.

The mission itself is straightforward assault on the target's defended base. Dispatched enemies may drop items like ammo on the ground, which shimmer brightly until collected; but corpses can also be looted for bonus treats. On the final approach, the target emerges from the door of his shack and the player has a choice: kill him outright, or disable him for capture.

This plays into the game's Honour and Fame system. Marston can gain or lose Honour depending on his actions. Capturing the target here boosts Honour, which ultimately affects the way the world reacts to you, from shopkeepers to the law. There are many ways to gain Honour, like aiding distressed travellers and helping the law; and just as many ways to lose it, like, as I discover, shooting hookers in the belly, however inadvertent. In short, murdering and stealing might get you rich quicker but it has consequences.

Fame is increased with every significant action Marston performs. Again, this impacts how you are perceived and treated, with townsfolk referring to you by name as your renown increases but, just as likely, cocksure meatheads challenging you to a duel. You might even blag a discount at the local store. Unless you'd rather shoot the shopkeeper in the face and steal everything.

With the mission complete I take the opportunity to wander off-piste and out towards a rocky rise. Much has already been written about the game's ecology system. There is a circle of life in Redemption, but not one of which Disney would necessarily approve. From rabbits to buffalo and bears, larger animals pray on smaller ones - and on you.

I shoot a rabbit from horseback and watch its bloody body slide down a rock face. It's worth dismounting to collect as animal skins carry a value and can be sold-on in towns. Skinning a dead critter is a single button press. You don't see the process; instead the camera shows Marston crouching down and getting busy with his blade, with the squelch of flesh and blood splatters on the screen indicating a job well done.

As a rule, as long as it ain't human, you can skin it. A cougar appears and I'm forced to resort to Dead Eye to take it down. One skinning later and all that's left is a rather unsettling feline corpse. But the cougar wasn't working alone, and before I'm able to do anything, another has savaged my horse to death. I shoot the cougar and slice off its settee cover. And then do the same to my horse. It's what she would've wanted. By the end of my playtime, I've resorted to Dead Eye shooting a horse limb-by-limb before tearing off its skin like I'm stripping a bed. I feel dirty and ashamed.

If you lose your horse (by fair means or foul), the game apparently detects when you've been on foot for a couple of minutes and creates a scenario whereby you can seize a replacement. That could simply be someone riding by, or a stage coach, or the appearance of a campsite with a horse tethered and waiting to be nicked.

Campsites play an important role. Others' offer an opportunity to sit, shoot the breeze and enjoy a narrative set-piece. But there's every chance of a knife being pulled on you, particular after dark, so it's advisable not to get too comfortable. Marston can also pitch his own camp, which becomes important as you explore the map, serving as an item refill and save point.

A second playable mission gives a taste of Gang Hideouts - side missions that provide a useful haul of items and treasure. In this case, Marston is trying to help a farmer whose daughter has been captured and is being held in a hideout. It's another engaging cover-and-shoot sequence; and once enemies outside have been cleared, a final, frenzied dash ensues to rescue the daughter before she's done over.

I pop a bullet in her captor to scoop maximum Honour and the eternal gratitude of her father. But, I'm told, if I'd arrived too late and she'd been killed I would still have received some Honour since I'd tried my best to help. If I'd just stamped on her head instead it would've worked the other way, no doubt.

The final playable mission is from later in the game. Marston calls on a shambling drunk named Irish, who knows the location of a Gatling gun he needs for a major hit. The only problem is it's stored deep within a heavily guarded mine. A tense shootout in tight, underground tunnels plays out, before the gun is retrieved and transported out in an entertaining mine cart sequence. At one point, I spot an enemy up ahead laying explosives on the track in my path; a panicked Dead Eye shot misses the explosives completely but kills the guy, while another shot successfully ignites the obstacle at exactly the moment the body lands on it, causing it to shoot backwards spectacularly as Marston and the cart zoom safely through the smoke. Yee-haw!

Of course, this being a Rockstar openworld game, even on a couple of hours' playthrough there's an enormous amount to see, do and speculate upon. A game of poker in the back of the saloon in Armadillo, ends in a ferocious firefight as I get bored, shoot everyone, steal their money and leg it.

Committing a crime in a town will result in you being grassed up to the sheriff, at which point your Wanted rating shoots up. This works like the stars system in GTA. To get the law off your arse, you need to get the hell out of the trouble spot and move beyond the area highlighted on the mini-map. That will lower your Wanted level allowing you to return safely, but won't remove your Wanted status - leaving you vulnerable to bounty hunters. To get rid of that, you can either pay off a fine or acquire a pardon letter.

There's so much more to say. I could talk about the vulture-shooting mini-game; the deliciously cruel potential of the lasso; the bad, bad thing I did in a church; collapsing unconscious in a bar after caning two shots of hard liquor (eerily similar to my own tolerance). And then there's multiplayer, which, according to Rockstar, will be part of the next reveal. I could go on, but like Grand Theft Auto, the joy is in the discovery and individual experiences.

Technically there are still rough edges that need smoothing out. The frame-rate plummets dramatically during particularly intense action sequences, and there are still noticeable bugs. But the rep says the game is basically content-complete, so the San Diego team is now locked-down in polish-and-fix mode.

Before this week, teased by assured demos and typically slick trailers, Red Dead Redemption was perhaps the gameworld I was most looking forward to immersing myself in this year. What little I've now directly experienced hasn't done anything to change that.

It's dangerous to draw broad conclusions for a game of this scale from such tiny samples, and there are many disparate elements here that need to work together to make a compelling, satisfying whole. But the potential at least is clear.

Rockstar has always had the best toys in the sandbox. The promise of an entirely new sandbox to try them out in remains an intoxicating prospect.