How arbitrary and clumsy it is to assign a score to a game on a point scale. Almost by default many games reporters feel obliged to leave that final point as a never-to-be-played trump card. To use it just once is to open a Pandora’s Box of flaming scepticism that they fear could combust their credibility and leave them out in the cold, sifting through the ashes of their career.

Ten, many privately hold, is a score best left to advertorial magazines, and to flirt with the thought of using it is to invite more hand-wringing than typing.

To truly score a ten, then, a game must surpass mere excellence. It must scale some kind of Olympian summit and boldly gaze upon the divine countenance of whatever deity it is that gamers worship. No kidding.

Red Dead Redemption is not just the definitive sandbox gaming experience, nor simply the best Wild West videogame (hardly a challenge), it is developer Rockstar’s crowning achievement to date.

It’s not unblemished – the occasional hiccough can prompt you to finally investigate that intriguing smell in the kitchen – but what passing few flecks of annoyance are there are so incidental that they have little tangible impact on the total experience.

An indirect sequel to the underwhelming Red Dead Revolver, Redemption is set at the turn of the 20th century and tells the story of John Marston, a reformed outlaw presented with a ruthless ultimatum by the federal authorities.

Now he must track down his former partners in crime who are still holed up in the last remaining bastions of the Old West – New Austin, Nuevo Parasio and West Elizabeth – places where a man is still free to make a dishonest living.

Marston himself is a manifestation of the era, caught between the unbridled possibilities of the West and the imminent strictures of civilisation.

Each region alludes to a real-world counterpart. New Austin and West Elizabeth might be Texas and Wyoming, respectively, while Nuevo Parasio is set in Mexico. Together, these three regions compose the largest gameworld that Rockstar has yet created.

It’s the promise of rewarding exploration that is the bottom line for any sandbox title, and within minutes, Redemption has you in the stirrup, drinking in the vastness of the American frontier.

The environments are stunning. From the dusty Catholic missionaries of Nuevo Parasio in the south to the snowy mountain passes of West Elizabeth in the north, the world is replete with character and detail. If you can see it, you can go there.

Were the gameworld empty we’d wager you could still traverse it for several hours without complaint, perhaps making for a distant ridge to take in the next arresting panorama, or investigating an abandoned chapel that once served a nearby ghost town.

But whatever the case, it’s not a wager we’ll have to make.

What Red Dead Redemption does, what separates it from the pack by more than a horse's length, is deliver on that sandbox promise. Beyond that bend in the road there's always an unpredictable encounter to experience – something to discover and involve yourself in.

Redemption’s world is full of random events. You’ll happen upon all number of situations as you make your way across the gameworld – local men carrying out mob justice on a petty thief, bandits hanging a man’s wife from a lone gnarled tree, a shootout between the law and a local gang, perhaps.

None of these events are preordained – whether you find a hanging wife is circumstantial – nor is how they play out. It’s quite possible the “distressed husband” who hailed you down is anything but, and has a mind to cut your throat and make off with your horse.

Nor are any compulsory. Instead, they’re offered to add interest, variety, danger and reward to the otherwise routine task of getting from mission cinematic to mission start.

You can invest hours doing little more than exploring the wilderness and indulging in the volume and variety of these happenstances. Just note that you’ll learn the folly of your unsaved ways when you discover that none of these incidental events generate a checkpoint.

Additionally, Redemption has a comprehensive ecology – something Rockstar has never had to consider before in the Grand Theft Auto series. The food chain runs from armadillo and jack rabbits to goats, buffalo and cows, wolves and coyotes, right up to mountain lions and grizzly bears.

Circling the carcasses of both man and animal are vultures, crows and eagles. These creatures all carry out their existences quite independently of anything Marston is doing. Of course if you want to, you can hunt them and sell their flanks and pelts - the farther afield, the better.

But most importantly, this is a game about the setting. There is a compelling meta-narrative to give a larger context to Marston's actions, but Red Dead Redemption rewards the player for making deviations along the way. As he explores the West, Marston can hunt for treasure, take bets for challenges, assist forlorn strangers or accept bounties. Mini-games such as horse shoes, five finger fillet and poker can occupy hours in themselves. And if you get bored, feel cheated, or are merely curious, you can always pull out your shooter to spice things up.

In order to make Marston’s actions consequential, the developers have included an interrelated fame and honour system. Fame measures how widely reported Marston’s actions are, honour denotes their nature.

With high fame, Marston will become a recognised figure and strangers will begin to address him by name, seeking him out to solicit his help, offering him discounts. But fame is a two-way trail: In time, every fresh-off-the-stagecoach aspiring gunslinger will also line up to bring down The Great John Marston.

Combat is a straight forward affair borrowed almost directly from the Grand Theft Auto playbook. Simply take cover and aim. Redemption also defaults to aim assist, but includes a free-aim mode.

The most noteworthy inclusion is the reprisal of Red Dead Revolver’s Dead Eye system. Triggering it slows the action and filters the camera through a whiskey lens. In this mode, Marston can paint targets with crosses before switching back to real-time to unload his piece in a hail of rapid-fire.

The Dead Eye mechanic is broken into three tiers. The first simply slows the action. The second auto-paints targets with crosses as you move the reticule over them. The third allows you to mark up the crosses manually, allowing you to shoot guns from hands, hats from heads, caps from knees.

The game’s physics run on a hammed up Euphoria engine. Marston’s foes will buckle and fold in finest spaghetti fashion, responding precisely to the location and scale of their wounds as he heroically outdraws the lawless West.

Redemption delivers a flush cast that includes eccentric snake oil salesmen, inspiring revolutionaries and volatile desperados. All manner of stereotypes have been lifted from the Saturday Matinee serials of yesteryear – the sorts of characters we want to discover drinking away their sorrows in the saloon of a one-horse town – and each is given a fresh coat of parody.

The soundtrack, too, is familiarly fitting – a compilation of harmonica riffs, droning trumpets, solitary guitar chords and lonely violin notes.

Indeed, the experience is very much in the tradition of Western cinema. To date, no videogame has managed to tap the rich vein of the Western – one that has come in and out of style over the years, but also one that has never lost its allure ever since Tombstone lawman Wyatt Earp hung up his spurs and rode out for Hollywood.

The unparalleled sophistication of Red Dead Redemption changes that.

Tell your god to prepare for bloodshed.