The Call of Duty series has become one of the biggest franchises in modern gaming. From a relatively auspicious start on the PC the games have grown, spread across multiple formats and – in large part due to the phenomenal success of last year’s instalment, Modern Warfare – taken over the world.

That game, though, was developed by Infinity Ward – whereas Call of Duty 5, dubbed World at War, has been put together by Treyarch, the same studio who made a bit of a hash of Call of Duty 3. It’s fair to say that a few people at Treyarch had a valid reason to be nervous when embarking on this particular development cycle.

This game instantly differs from Modern Warfare, though, by returning to WWII – the conflict that provided a catalyst for the Call of Duty series to begin with. Rather than replaying the same tired sequences that have been offered in a thousand mediocre shooters, Treyarch has put admirable effort into uncovering some of the more unusual theatres that really emphasise World at War’s all-encompassing title.

It’s this global theme that sees the opening sequence of the game take place on a Pacific atoll, where your crack team of Marines – and you, Private Miller – are set to take out a small Japanese base. You’re instantly thrown into some frenetic, action-packed – and typically Call of Duty – gameplay, with gunfights, grenades and garrotting the order of the day.

While this sequence – that sees you first fighting your way across a beach, and then inland – acts as a superb introduction to the frantic and explosive gameplay that we’ve come to expect from Call of Duty, it’s also an early showcase as to some of this game’s problems.

The linearity shines through, with your character – a lowly Private – being the only one capable of triggering the next part of the level. If you don’t fancy leading from the front, you’ll be stuck in the same place, fighting endlessly respawning Japanese troops before you do it all again in the next part of the level. It’s a small kick in the teeth for realism, even though everything feels suitably explosive and war-like, and a problem that wasn’t so evident in Modern Warfare.

Some of the controls can be a bit fiddly, too – holding down the L3 button to run, for instance, all too often descends into a scramble that results in you pointing your weapon around and looking silly before you’re set upon by a relentless Kamikaze troop. In a neat touch, though, you can use your last breath – and the R3 button – to knife him in the neck before he can do the same to you.

Thankfully, the action picks up somewhat: wherever you’re fighting, be it on tropical-looking islands occupied by Japanese forces or in a typically ruined – and desolate – Eastern European towns, it’s always frantic and packed with enemy troops and deeply impressive set pieces. It’s a shame that the linearity shines through a bit too often, but it’s not too noticeable as you’ll often be far too busy trying to shoot everyone in sight and reach the next checkpoint.

It’s fun to play, then, but it’s also worth noting that few of World at War’s so-called climactic moments – from the introductory sequence on the atoll to several incendiary missions further on in the campaign, including raining bombs on a Japanese village or shooting down enemy ships – quite match up to their equivalents in the last game for scale, scope or impact.

World at War is built on the same graphical engine as Modern Warfare and, generally, it looks just as good – character models in particular are immensely detailed and add character that, when compared to your trusty group of comrades in Modern Warfare, is sometimes lacking in this game. Unfortunately, the odd graphical glitch spoils a bit of the realism – the occasional blurry texture or slow-motion explosion reminds you that the PS3 version may have got the short straw. The frame rate resolutely stays rock solid throughout, mind, with no evidence of slow-down.

As well as trying to out-do Modern Warfare on gameplay alone, Treyarch has also been busy adding new features. Co-operative play supports up to four players tackling the majority of the game’s levels at once – although some levels, such as sniper stages, are left out for obvious reasons. It works well, and helps add to the emotional connection between squad-mates that can sometimes be lacking in the single-player campaign.

There’s even a silly mode called Nazi Zombie: you’re in a bunker and being attacked by wave after wave of, well, Nazi zombies. It harks back to ancient games like Smash TV, where you just have to survive as long as possible – and it’s quite a lot of fun. The stunning multiplayer from Modern Warfare returns and, perhaps wisely, Treyarch haven’t tinkered with it too much, simply adding more rewards and bonuses.

It’s also worth mentioning the aural experience that World at War offers. Hollywood voice talent, in the form of Kiefer Sutherland and Gary Oldman, have been roped in, and their obvious skill shines through with some superb voice acting. The rest of the sound is fantastic, lending frantic moments even more atmos and gravitas.

World at War is a difficult game to call. In one sense, it’s absolutely fantastic: the gameplay is mostly spot-on, it’s an enormous amount of fun, it looks and sounds (mostly) awesome and the excellent multiplayer returns. On another hand, though, the linearity is a bit too forceful, and it can’t quite match up to the tour de force that Modern Warfare provided, even though it still stands head and shoulders above almost everything else for both absorbing gameplay and atmospheric, war-torn levels.

Still, there’s no shame in coming second best to the game of the year. This is slightly less of an essential purchase than Modern Warfare was – and multiplayer aficionados may wish to stick with the last game rather than splash out on essentially the same elements. If you’re hankering for some World War 2 action after last year’s contemporary foray, though – and are intrigued by the fresh perspective on the battles and the co-operative play – then this would be an excellent purchase.