Diminishing returns is a criticism that we thought we'd never find ourselves having to level against the Assassin's Creed franchise. After all, Ubisoft has always been canny with what's fast becoming its flagship IP, spinning out Ezio and Altair's story beyond the mainline series with smartly pitched, lucrative spin-offs and new multiplayer modes. While you could argue that AC: Revelations was a game too far however, it appears that Ubisoft Montreal is resolute in its direction for Assassin's Creed III. Diminishing returns this most certainly is not. It looks like it could be the shot in the arm the franchise needs in fact, and if that also means bidding farewell to those stinky first-person block puzzles, then it'll be all the better for it.

Assassin's Creed III takes the American Revolution as its setting, placing new hero Connor at the centre of 30 years in US history between 1753-1783. Connor (birth name, Ratohnhake:ton) is half-Mohawk Indian, half-British, which informs the motivations and customs of the character. Initially, Ubisoft gave Connor the ability to claim scalps for instance, until research into Mohawk Indians revealed that they never took the scalps of their victims. As usual, the dev team have really done their homework for ACIII, ploughing months of the game's more than two years of development time into ensuring that the game is as historically accurate and authentic as possible, exaggerating certain aspects in the name of gameplay, of course.

Divided into three main areas, there's a real sense that Assassin's Creed III is even more vast than previous instalments too, with Ubisoft's Director of IP Development, Tommy Francois telling us that the snowy forests of the Frontier zone alone are more than 1.5 times the size of AC: Brotherhood's Rome. That's before you even factor in the bustling wide avenues and ports of Boston and the streets of a New York under siege. The latter area is under wraps for now, but during our presentation, we're given a good look at the Frontiers with its copious trees to climb and its intricate wildlife ecosystem (an idea that pre-dated the launch of Red Dead Redemption, says Francois), the sprawling muddy battlefields of Bunker Hill and the stone-paving, market stalls and people of Boston.

“History is our playground,” comments Francois, as he proceeds to show us outstanding gameplay footage of Connor struggling through knee-deep snow, stumbling upon a dead body holding a note. From seemingly out of nowhere, he's attacked by a bear that rears up and falls onto the end of Connor's blade. This is a clean kill, granting Connor a perfect pelt should he choose to skin the animal. You can shoot an animal with a musket if you like, but you'll get a bullet-hole riddled pelt for your dirty kill. As a Native American, Connor respects nature, so blasting a deer in the face with a rifle isn't exactly in keeping with his character, which is why you're rewarded for slaughtering fauna with your knife or tomahawk rather than peppering their hides with shot pellets.

Assassin's Creed III utilises the new 'Anvil Next' engine, which is apparently capable of some remarkable feats. Climbing a rock face, Connor moves with a fluidity inspired by pro-rock climbers, and he can leap between the boughs and branches of trees with the swiftness and grace of Ezio and Altair before him. “It was one of the most challenging parts of developing Assassin's Creed III,” say Francois, in relation to the tree climbing. Connor can scale trees with typical athleticism, swinging between branches just as gracefully as he clambers up sheer rock faces. He appears perfectly at home in both organic environments and heavily populated areas.

Speaking of which, the new Anvil Next tech enables Ubi to render up to 2000 characters on screen at any one time according to Francois, leading to some truly spectacular views on the battlefields, as muskets fire from large platoons and cannon fire sends clumps of earth flying into the air. Connor can weave his way through all sorts of topography, sliding under arched tree trunks or leaping over rocks with speed and agility. This also extends to Connor's combat prowess and he makes Ezio and Altair look like rank amateurs by comparison. Connor steams into confrontations, and can take down enemies in seconds with his dual-wielded knife and tomahawk, dual flintlock pistols and rope dart with jaw-dropping balletic moves and counter attacks. His fighting style is blindingly fast, and the revamped control scheme should not only make movement and traversal easier, but based on the combat portions we're shown, tackling multiple antagonists at once will be less stilted and stop-start than before.

Connor's rope dart meanwhile, is the replacement for what was originally conceptualised back in December 2010 as the 'chain blade', a hidden blade upgrade that enabled you to launch the pointy bit into an enemy before dragging them towards you or hanging them over a tree. The chain blade was deemed too fantastical and removed from the game, but the rope dart – based on a device from Chinese history – serves the same purpose. This attention to detail and historical authenticity is referred to during numerous junctures of the gameplay demo, such as Major General Israel Putnam's actual “whites of their eyes” speech that he's delivering on Bunker Hill as Connor arrives on the battlefield, and the atmosphere of the Boston streets, bolstered by up close and personal interactions with NPCs.

Simply walking along the docks, Connor's hassled by a market seller who follows him for a while, before a bellowing news boy asks if he'd like to buy a newspaper. A woman drops a crate of apples and a thief instinctively picks one up and runs off with it. You could chase the man if you want, or ignore it completely. There'll be loads of emergent moments like these. Soon, Connor comes upon customs where he's asked for documents he doesn't have, so it's time for a classic Assassin's Creed pursuit through the crowds on foot, which is where the free-running comes into its own once again. This time however, you're able to jump over moving objects, leap over and under obstacles, bound your way up into trees, through windows, into and out of interiors with deft agility and speed, before arriving on the rooftops to admire the beautiful vistas, confounding the soldiers who've been futile in their attempt to give chase. It's breathless and typically impressive Assassin's Creed fare, that also serves reminds us why the series is such a blast to play.

Social stealth is still a key part of Assassin's Creed III, so blending with crowds and interacting with NPCs, including a range of historical figures like Charles Lee, George Washington, Gilbert du Motier de Lafayette and Benjamin Franklin is very much a major part of the game. Key encounters like these show off the game's impressive new motion-captured cinematics, which according to Ubisoft, mark a video gaming first. They're fully mo-capped from head to toe. The entire performance. And the faces have more bone structure around the eyes and mouth than before, so the characters not only look and behave believably, but the cinematics look more involving than before. Details like animated fabrics add to the increased realism that Ubisoft is shooting for.

If you thought that the Assassin's Creed franchise might be on the wane, our first look at ACIII has blown our preconceptions right out of the water. It looks and sounds like the most ambitious game in the series yet, with the all-new presentation based on the 3D Animus core just the icing on the cake. As ever, the attention to historical and visual detail is looking impressive, and additions like snow, rain, fog and other forms of weather promise to keep the game's world nice and varied. Divided into three distinct locales, Assassin's Creed III also promises to be even bigger than previous instalments, but it's the smaller moments that we're looking forward to the most. Tracking targets, following tracks and blood trails in the snow, hiding, poised and ready to strike in foliage or scoping out the enemy from the treetops. It's Assassin's Creed alright, but Assassin's Creed III could potentially be the most exciting and ambitious entry in the series yet.

Assassin's Creed III is out on October 31st, 2012.