A shadowy figure grills Dr Catherine Halsey about the Spartan programme at the opening of Halo 4. His questioning is all about loose cannons and dubious origins, old chestnuts promising ethical questions that never really materialise. But near the end of the prologue, the interrogator becomes more confrontational, attacking Dr Halsey on the subject of the Spartans' "basic humanity". He accuses them of "exhibiting mild sociopathic tendencies", of "having difficulty socialising." Then he takes aim at the Spartan programme's greatest achievement, a figure we've known and treated as a hero for eleven years. "Do you think the Master Chief succeeded because he was broken?"

The question of whether Master Chief can actually care pervades Halo 4. His relationship with his distastefully-designed AI companion Cortana takes centre stage, as if directly addressing the interrogator's accusations. Cortana has developed rampancy, a kind of AI schizophrenia that kicks in after seven years, tearing the intelligence apart by making her think too much. Rejecting the possibility of losing his closest friend, Master Chief resolves to get her back to Dr Halsey, to get a cure. This quest doesn't drive the narrative forward - the third-level introduction of grizzled Forerunner eugenicist The Didact commands the story in a disappointingly familiar way - but it looms over the action like a particularly melodramatic shadow. 343 Industries has set out to bring more emotional heft to Master Chief's superobjective than Bungie ever did, imbuing the same old "gotta save the planet" routine with relationships built on more than a common enemy or old-fashioned Marine Corps humour.

Halo 4 review

To its credit, the studio gets most of the way there. The voice actors do a commendable job with some of the ham-fisted, consciously 'sad' dialogue - Steve Downes captures Master Chief's struggle to come to terms with his partner's deterioration well, and while Jen Taylor's vocal performance has more than its fair share of dud line-reads, she never makes Cortana seem like a helpless damsel in distress, finding strength in her fear. More effective are the ways Cortana's rampancy manifests itself in-game. Her struggle briefly, periodically becomes the player's struggle as waypoints flail, the HUD fizzes with static, and her doubts and anxieties start to spill through her carefully-maintained facade of wisecracks and jargon. By bringing the rampancy into the game, having it affect the way Chief perceives things, the story gains an urgency, a personal edge that simply wouldn't be there if the rampancy had been ignored outside of post-level cinematics.

343's attempt to bring emotionally mature material to the Halo series marks one of the few departures from the narrative template Bungie crafted over ten years ago. The shift to the oft-mentioned, rarely-seen Forerunners as primary antagonist offers little more to the narrative than slightly higher stakes and a damp squib of a finale. The Covenant are inexplicably also present, 343 has switched out their cartoonish charm for a grotesque kind of photorealism. Master Chief calls them "more fanatical" than those in the original trilogy, a judgment seemingly based solely on their overtly-reptilian appearances.

Halo 4 review

That said, there's a lot to recommend in the campaign, the franchise's strongest since Halo 2's tale of an alien experiencing a crisis of faith and the cyborg messiah he falls for. For starters, the enemy AI has noticeably improved. On Normal, Covenant forces are marginally wilier and slightly more willing to work as a team than they were five years ago; meanwhile, The Didact's Promethean footmen - fire-spitting dog-bots called Crawlers, sword-wielding bots called Knights, and Watchers, aerial support reminiscent of the flying Attack Droids in Beyond Good & Evil - employ simple but clever attack plans, providing each other with defence, reinforcement and coordinated distraction in a way that contrasts with the Covenant's individualist, scatter-and-see-what-happens pseudo-strategy.

The player is subject to a corresponding onus, one that demands more attention is paid to how the game is played. For example, the number of weapons available to the Chief has ballooned, with a whole bundle of fun laser-based Forerunner weaponry now in the mix. With that, however, ammunition conservation is more important. Ammo drops are less frequent, guns go through clips and charges at a much faster rate, Promethean enemies are harder to kill, and the most common weapons, such as the inaccurate Suppressor or the tinny, hard to aim Boltshot, aren't exactly desirable. It's a canny way of making the threat seem more formidable, and a welcome invitation to players to put more thought into the way they approach a combat zone. It almost makes the continued shunning of dual-wielding forgivable.

Halo 4 review

These small but significant improvements to the narrative and plot are nothing compared to the aesthetic improvements. Halo 4, as a visual and aural package, is superlative. From the opening level, in which 343 harks back to old escapades on the Pillar of Autumn and Cairo Station before rudely and beautifully ripping the homage apart with a giant gravity well, Microsoft's hired guns prove themselves to be adept crafters of spaces and architects of set-pieces. Dampening Bungie's legacy of beige hues and straight lines, Halo 4's environments frequently pop with colour and variety. While the nine levels never really come together as a world, per se, there's a lot to be said for the awesome beauty of the jungles of "Infinity", or the seamless integration of the mechanic and the organic in "Requiem", or the cavernous and beautifully-lit orange-and-blue chambers in "Reclaimer". When coupled with Neil Davidge's phenomenal score - a piece that marries Davidge's moody trip-hop roots with a more traditional orchestral score in ways both atmospheric and triumphant - it's easy to say that Halo 4 is worth it purely for its sensory delights. Even the freshly-scaled Covenant have a gruesome appeal to them.

Alongside standard Campaign co-op, 343 has split Halo 4's multiplayer, dubbed Infinity, into two specific categories, War Games and Spartan Ops. The former encompasses the new competitive multiplayer, while War Games welcomes back old faithfuls such as Slayer, Oddball, and Infection (renamed Flood, in case you hoped Halo 4 was totally turning its back on them), as well as introducing two new game modes, Domination and Extraction.

Halo 4 review

Both modes are reminiscent of the point-capture mania of Territories. Extraction involves teams setting out to extract information from two beacons, with a new one replacing every beacon successfully captured, while Domination has players try to capture three 'fortresses' around the map, points that are sporadically fortified upon capture with turrets, shields, vehicles and weapons. Domination is by far the more successful of the two, and is easily one of the best additions to Halo multiplayer since Grifball, if only for the frantic "last man standing" manhunt that begins once a team has captured all three fortresses. In general, though, War Games is comfortable and engaging, a classic Halo multiplayer experience with a handful of tweaks and maps that are a little too cluttered for their own good.

The other mode, Spartan Ops, has been put forward by 343 as a small revolution in Halo multiplayer, providing a rich cooperative narrative that also fills in some holes in the main campaign. While the idea is fantastic in theory, and the mode's episodic nature means that there could be some incredible narrative twists just waiting to be unleashed, there's nothing on day one to suggest this is anything more than an uninspiring mash-up of Call of Duty's hoo-rah Marine-isms and Halo's alien murder sprees. The characters are poorly-sketched future-warriors with either a bad sense of humour or none at all, the narrative is little more than anodyne bug-hunting with some casual sexism and an artefact thrown in for good measure, and the emphasis on wave-based combat gets tedious fast. There's still a lot of time for Spartan Ops to get better, but the package as it's presented is little more than a lightweight annex to the main product.

The Halo series has always had shortcomings - the clumsy, jargon-filled dialogue; the switch-hunt levels; the underdeveloped characters. Halo 4 tries hard to avoid those potholes in the road ahead, and 343 Industries makes a fair fist of it. Levels are broader and more varied, small alterations have been made to force the player to put more thought into how they craft their experiences, and there's some genuine emotional content being experimented with. The whole enterprise does end up feeling a bit too earnest, a bit too forced, a bit too cornball. Despite that, though, there's a maturity of vision to Halo 4, one that manifests itself, in small ways, in the narrative and in the ways you interact with that narrative. 343 isn't content to let Halo stagnate, and the direction it want to take it, for now, is welcome indeed.