You'd think a new map pack would be the ideal jumping on point for Call of Duty - everyone's in it together and all that, mainly because nobody knows which hedge is tactically the most efficient to hide in, and there will surely be some thrilling community camaraderie as you all work together to learn these brand new levels one by one.

Wrong. Hopping on a new Call of Duty map pack the second it comes out is like a testing ground for the most devoted, besotted worshippers of the franchise. You'll be pitted against people who can shoot with pin-point accuracy, probably bending the laws of physics to their whim (or, if you were playing online games when I was a kid, just using cheats) and completely ignoring things like weapon recoil, while at the same time having some sort of inherent understanding of the new layouts before you've even discovered the shutter doors can be toggled on Stockpile.

That's probably why Activision has opted for an alternate marketing tactic in the run up to Escalation, Call of Duty: Black Ops' second DLC pack, thrusting its co-operative Zombies mode into the limelight and having the four competitive maps play the rest of Girls Aloud compared to Call of the Dead's Cheryl Cole.

We'll start with Call of the Dead, then, which itself opens with George Romero narrating about his love of zombies while on the set of a movie featuring Robert 'Freddy Krueger' Englund, Michael 'Henry Lee Lucas' Rooker, Danny 'Machete' Trejo, and Buffy 'Sarah Michelle Gellar' the Vampire Slayer. This elongated opening gets a little bit irksome after about, ooh, the second time, but I suppose when you've got George Romero providing voiceover you want to get your money's worth. And most of it can be skipped after the map loads, too.

The real twist to the normal Zombies rhythm is that Call of the Dead has an undead and virtually invulnerable George Romero chasing you around, shifting the focus from battening down at key locations, racking up the cash required for advancement, to performing delicate laps of the arena. You've also got to keep your distance with the zombified director on your heels as attacking him directly causes him to go berserk. Then there's a bonus side mission to rescue Nikolai Belinski and the rest of the original Zombies quartet, but you've got to embark on a rather long and fiddly series of fetch quests that I still haven't quite been able to manage.

It's not reinventing the entire Zombies gametype, but Call of the Dead does add a nice bit of variety to the roster. There are a couple of new additions, such as the V-R11 gun that can turn zombies back into humans and a Deadshot Daiquiri perk which boosts your accuracy, but it's a shame Treyarch doesn't employ the same individuality with its characters inside the mode as we see in the lavish introductory sequence. Players are teased with scenes of Trejo sporting machetes and Rooker with double shotguns, before having everyone start on round 1 clutching their pistols - failing to fully incorporate the spirit of the introduction is a missed opportunity.

And while you might get lured in by the glitz of Call of the Dead, you're more than likely to stick around for the adversarial maps. On this front Black Ops' staple multiplayer modes are bolstered with a cache of four: Hotel, Convoy, Zoo, and Stockpile.

I tend to play Call of Duty on the periphery, cruising around the fringes of the map, afraid to step into the active warzone taking place in the middle, so a few laps around Hotel can be a lonely experience; it's simply too big for this kind of play. You've got to get stuck in at the core, unless you're that one sniper on each team who'll get locked into an immediate and permanent duel across the courtyard on the right hand side of the map.

Hotel strikes me as a mix of Modern Warfare 2's Bailout, with plenty of right angles and close-up confrontations but fewer prominent sniping opportunities. You get to drink in the leisurely sights of a pool, a steam room, and follow the ornate hotel lobby around to a check-in desk before branching out into a small casino and plush upstairs halls. I think the setting is more of a bona fide Cuban resort than a hotel, but when glass is shattering and bullets are screaming through the air I doubt you'll care much for the distinction.

You'll have fun with Hotel when messing around with the elevators in the centre of the map. Call a lift down, pop a claymore inside it and send it back where it came from - laughs a plenty when people get exploded as they investigate after the doors whoosh open. But people will get used to that after a week, and everyone will just avoid the spot like so many of those stereotypical DLC gimmick additions which came before it.

My problem with Hotel, however, is that it feels too much like work. There are far too many elevated positions that are easily locked down, thus encouraging people to camp out in little clumps. It feels like Treyarch is falling down a little here, over-designing their maps around this idea they need to justify the DLC asking price with impressive geometric constructions.

Stockpile will go down well with cowardly snipers; it seems to be the most capable faraway blaster included in the pack provided you're nimble enough to move locations between shots. The tumble-down environment is constructed with lots of little buildings framing a larger construction in the centre, and the location of capture point B if you're playing in Domination. Just like the city of Rome, all roads lead to B, so as you get to grips with the environment you'll end up there without even realising it. None of the other houses have particularly stunning lines of sight, but are mostly used for overlooking the areas housing the other two capture points.

The map seems to be too much of a clusterfudge if you're inside of B but, conversely, too barren when you're outside of it. Stockpile is the kind of map where you'll dart about for a few seconds before throwing caution to the wind, blowing the dust off your shotgun build and blazing around the map like there's no tomorrow. Which, if my general performance is currently any indication, there probably won't be.

Moving on, then, and we'll detour through Zoo. This isn't one of those, you know, fun zoos with animals. No, it's a desolate abandoned zoo squeezed through Treyarch's very finest desaturated grime filter. I don't know why every map in Escalation needs to look like the environments have had any noticeable sense of warmth or joy completely sapped out of them, but Zoo is even more depressing to look at than Carnival from Modern Warfare 2.

There's a miserly monorail and a wretched jungle environment to spark things up a bit, but it's an even browner experience than Gears of War boiled down to its maximum concentration. The monorail offers little tactical advantage and leaves you completely and utterly exposed, but that doesn't seem to stop everybody rushing for it from the word go. It's quite a lot of fun poking your way through all the bedraggled attractions, however, and the map has been decently constructed so it zips along at a nice rhythm. Zoo looks ugly but leaves a nice impression.

Convoy is my personal favourite. The map employs the series' most immediate vignette - that of a destroyed suburban America - and mixes it with Black Ops' tableaux of sixties Cold War fears. Strewn across the Californian map is a wrecked missile convoy, with the expensive ordinance itself scattered along its roadside, and the colour palette is infinitely more versatile than most of the other offerings on show.

You ferret around twisting gas stations, motels, and mom and pop's diners in a bid to either get towards or away from a central highway, a deadly environment in itself with elongated passageways and deep reaching lines of sight. Convoy is one of Black Ops' most balanced maps to date, accommodating the aggressive desires of churlish AK-74u ruffians and the self-protective needs of sedentary longshotters.

There are still a few too many gimmicks in Escalation for my tastes - Stockpile's garage doors are very much Escalation's useless ziplines - but there's plenty of variety on offer, and the quintet of new competitive maps will slot extremely nicely into the broader rotation. Call of the Dead is an interesting addition, too, and despite not capitalising on the full potential of the cast it's still a noticeable and enjoyable change in pace from what's come before.