Right now, the developers of Mercenaries are probably trembling in their offices, praying to whatever gods they worship that the vast shadow of San Andreas doesn't fall over their masterpiece. Because, make no mistake, everyone will be making the comparison. And for this we're more than partly responsible, what with our 'Grand Theft Warzone' feature two months ago. Thankfully, we're pleased to report that, although Mercenaries is built on the same free-roaming, do-anything principles, the experience is deliciously fresh. It is, without question, going to go down as the definitive PS2 war game. And, strikingly, that's without any of your fancy co-operative squad-based online nonsense. Phew.

Sure, at the very beginning - when you're thrown into the Korean warzone with only the briefest of briefings and no offer of rescue - you can't help but notice the familiarities. Played the demo yet? Noticed the near-identical controls (Triangle to jump into tanks, cars or aircraft and X/Square for acclerate/decelerate)? But, in this case, familiarity breeds contentment rather than contempt. Mercenaries takes the 'toybox' template and throws in a grenade-shaped rattle. Where GTA swaggers with criminal menance, Mercs has the giggle of a pyromaniac.

After only an hour you'll understand why one of the promotional slogans is "Playground Of Destruction". Hijacking a civilian car, driving to snowy plains, jumping off, commandeering a tank, ordering your aerial support team to level a building then juming in a helicopter and flying off into the sunset... outside of the obvious, no other game offers such alluringly varied thrills. Using the familiar control system is a masterstroke, made even more notable because the on-foot action is a huge improvement over San Andreas. FPS-style shooting and aiming has been adapted to work elegantly and in the third-person perspective. Instead of a spazzy lock-on system, the game guides your hand with useful yet subtle auto-aim, making targetting quick and easy. Clearly, the near-identikit setup is just a devious plan to get under your skin immediately, winning you over from the outset so you can stand back and appreciate what a different and wonderful game Mercenaries really is.

Let's be honest: the cityscape of comparable games are packed with repetitive journeys from A to B. Mercenaries is not. It is 'go somewhere, blow it up, win' at its most basic, and 'go somewhere, blow it up, capture enemy, win' at its most complex. It's a devious game of hide and seek, played by sadists with access to weapons of mass destruction. Landing in the warzone as a privately contracted bounty hunter, it's up to you to help look for war criminals operating beyond the reach of the allied forces. Your targets are numerous - 52 in all, given code-names taken from a pack of cards - but to get them all you'll have to make contact with each of the military forces making powerplays in the area, and then delicately attempt to keep all your paymasters happy, despite their contradcictory goals. That means complying with the Chinese forces for some missions, striking against them for the Russian Mafia on others and avoiding slaughter while you're working for pansies at the Allied Nations. The idea behind the quasi-realistic setting and the deck of cards motif is to create devices that make you believe in the world of Mercenaries, but they're exaggerated to great effect. The result is a compelling, but also darkly comic military atmosphere. So the opening movie doesn't introduce you to the characters of the story with a flashy CG sequence - instead, it uses harrowing news footage and a mock PowerPoint presentation with comedy arrows marking out the bad guys and how to profit from them. From the off, it's clear that the game paints its picture with broad strokes, with the emphasis firmly on your entertainment and involvement. And once you're in, the sparkly visuals lock the door behind you and then nail it shut. The vast battlefield is a wasteland choked by a grey oppressive fog, while the cities are grimy and sparsely populated. The few pedestrians are outnumbered by rolling tumbleweeds, litter and ranging cannon fodder.

What really makes Mercenaries so special is the way it uses its gloriously rich visuals to offer massively kinetic and adaptable missions. It may not have a bustling urban backdrop, but Mercs is all the better for it because the entire warzone is ripe for the taking. This is one game that genuinely lets you tackle obstacles in different ways, in terms of your approach territorially, the way you plan tactics for each mission or have to improvise in the middle of a frantic battle. The goals may be predetermined but the path with which you approach them is entirely up to you. Think of it this way; Mercenaries kicks San Andreas' later linear on-foot missions into the ground, grinding its heel until all memories of casino heists and mansion infiltrations are dust.

Our assault on the Ace of Diamonds halfway through the game provides the perfect example. Each Ace mission takes place on an island away from the normal warzone. Although this creates a less-than-organic boss-battle structure that's slightly at oods with the freedom elsewhere, these set pieces enable some real standout moments. Dropped off on the island's shores, the aim is to find the Ace and take him down - and the Diamond's boss is no different. He's got a massive supergun to be taken out - and the island has pockets of radiation (from other weapons tests) poisoning the roads. Walk into these areas and your in-game vision will go blurry. Coupled with the masses of vehicles populating the island, the tactical possibilities are near infinite.

Admittedly, we died numerous times trying to find a way that suited us (and, thankfully, the game offers to let you restart a mission straight away - there's no arduous drive back from the hospital), but the experiments were incredibly varied. Do we grab a tank and charge through the radiation patches, hoping those men hidden in the bushes with rocket launchers don't destroy the tank? Or trek over the hills, sneaking up on the footsoldiers? Or follow the coast around the island to one of the bases, where we can steal a van and covertly drive to our target while disguised as the opposition? Or get it potentially very wrong and walk over a hillock, straight into an APC's cannon, crying "Oh, you bastard!" just before being shredded into mercenary mush... Although we weren't really outgunned by them because a quick tap of Triangle let us commandeer the enemy vehicle, our mercenary beautifully grabbing the cannon, swinging up on top and taking out the driver.

You really do feel as if you're in the midst of militarised chaos, but you never feel overwhelmed or unfairly treated. And as for how you battle foes on foot? Crucially, you can only carry two weapons at once - one in hand, the other strapped to your back, which you can switch between with R2. Meanwhile, L1 and L2 relate to swittching between and throwing stun and standard grenades. This might sound restrictive, but it's actually a pleasure after games that inexplicably let you carry pistols, assault rifles, sniper gear and rocket launchers with room to spare for loads of ammo. Despite the arsenal in those games, you still often end up feeling like a boy scout armed with a rubber band catapult. But that's not the case in Mercenaries. Being limited to two weapons forces you to be tactical and to seek out the combination of weapons you prefer. Our regular combo setup was an RPG rocket launcher with an assault rifle, swapping to heavier machine guns, and anti-aircraft rockets, when required.

Plus, your offensive capabilities extend far beyond what you can carry. One of the best-implemented elements is the way you can order weapons, supplies, vehicle drops - even massive artillery assaults - at the touch of a button. You'll find yourself wishing the same technology - where you spent the moeny earned from completing contracts at the Russian Mafia's online store accessed via your in-game PDA - was avaialable in other games. The in-game economy fits neatly into the way you manage your relations with each faction, since you need to keep the Russians sweet in order to access their fascistic QVC. And having a crate full of health packs and ammo being dumped next to you during a tense battle is a massive thrill. Your mercenary's life is punctuated by moments where, health dwindling to 3% and low on RPG rockets, you cackle wildly as the crate touches down. Once it's cracked open (using the melee attack with Square) you turn your new toys on the baying henchmen, screaming with relief and enthusiasm as you unleash full metal justice.

This is just one of many massive conveniences that underlines what a bombastic experience the game is, constantly encouraging you to get back into the line of fire and rewarding you for being a free-thinking military anarchist. Take down key monuments and buildings - statues dedicated to evil dictator General Soong, for instance - and you're rewarded financially. You'll also get a cash bonus for each secret blueprint of national treasure you find boxed up at enemy basses (Mercenaries' war-warped take on secret packages, oysters and horseshoes).

In many respects, however, it's the vehicles which are the dealmaker, given that they enable you to travel through this world. We may have mentioned how the driving controls are identical to GTA, but the variety of military craft at your disposal out-classes almost any other game - there's no box-ticking just to be sure every base is covered. Tanks, civilian cars, helicopters, large artillery - there are different versions of each, some strictly owned by certain factions (such as the North Korean's stealth copter) and there's an impressive solidity to all of them in terms of steering, weaponry and armour. Choppers are particularly smooth to control and one of the game's highlights - even though a weird encircling corona intrudes on your field of vision while viewing the ground. Once you've had a taste for air combat, it's hard to keep your feet on the ground thereafter.

Fortunately, the mix of vehicles aren't in a chain of command where you'll end up resenting lower class transport - everything is useful in its own way, and how you use them throughout is one of the defining parts of Mercenaries' dynamic. You'll always have a soft spot for the M1025 Scout you start with, but you'll be grateful that you can order that Hummer from the Merchant Of Menace or steal that transport chopper from the South Korean HQ. It's the most important and alluring part of the game, giving you an immense feeling of freedom. Plus, at any moment you can break free of the missions dished ouy by the factions, grab a vehicle and search for the cards whose location can only be found through intel acquired on side-missions. To unwind, you can just roll around blowing stuff up - improving your cash reserves and reputation. When you're in the driver's seat, the atmosphere, and even the rag doll physics that show little men blown clear of the wreckage with each explosion - all come together to create a cohesive world.

Which means it's a bit of a shame that every now and then you hit a bump in the road and discover the occasional glitch. For instance, although there are numerous stretches of water, there are no boats to control and your character can't swim very well - something that feels even more at odds with the game's "go anywhere" mission statement. But arguably the biggest irritation is caused by, of all things, trees - the slenderest of which can't be demolished by the game's heaviest tanks, even though metal posts and fences crumple like cardboard! Forestation, meanwhile, acts as a boundary on some areas, but creates an invisible wall when clustered together - and you can't hide in the foilage once you've been spotted either - the overzealous AI will find you in seconds. And the same trigger-happy AI also extends to friendly troops who open fire and blow your cover.

Ultimately these frustrations are tiny blemishes on an otherwise immaculately presented gaming experience. Mercenaries' foundations are rock solid. It's easy on the eye and immensely satisfying to play, painting a picture of a warzone that isn't necessarily realistic but is deliciously overblown and ripe with potential. As the first big release of 2005, Mercenaries sets a high standard for the rest of this year's line-up to follow.

In our GTA San Andreas review, we asked where PS2 gaming would go next. Who'd have imagined that, just one month later, we'd have an answer to this: it's gone to the Korean demilitarised zone, and we suggest you book a flight there immediately.

Graphics 99%
Pushes the PS2 to its limit.

Sound 80%
Great FX and score, amateurish voicework.

Gameplay 90%
Exceptional with only slight hiccups.

Lifespan 90%
Real flash-bang for your buck.

Overall 90%
What a way to start 2005. Near-limitless in its scope and power, Mercenaries is the first brilliant game of the year - don't miss it!