Say hello to the last word in first-person shooters...

It seems fitting that Half-Life 2 should be released on Xbox now. With the console preparing for the 360 to take over, and with such fervent interest in all things next-gen, it's easy to overlook the immense power the current Xbox still wields. The Xbox needed Half-Life 2, so it could prove once and for all that it's the king of the current generation of machines, and it needed it to show that even at this late stage in its life, serious developers are still willing to produce serious software. And here it is, Half-Life 2 the pinnacle of Xbox gaming. We are slack-jawed in amazement at what we've seen. You'll be hard pressed to find a more intelligent, involving and entertaining game on Xbox today - it even gives Halo a run for its money.

Where to begin? Half-Life 2 is so much more than simply a good FPS - it's also an incredible feat of programming. Since rumour spread that it would be ported over from PC, gamers wondered how it could possibly be done. All that scope, vision, intelligence, and breath-taking gameplay - was it really possible to bring it to Xbox?

We were bracing ourselves. We were expecting to make allowances, to forgive corners cut and levels slashed, but Valve has achieved the impossible. You can almost see the Xbox sweat with all the work it's being asked to do, but it does it, and does it damned well at that. Textures and scenery, sound and lighting, draw distances, environmental detail - it's all there. Half-Life 2 never falls down, it never falters, and it never fails to deliver every moment with explosive efficiency.

Gordon Freeman's struggle against the alien invaders and the Orwellian government seeking to suppress and 'protect' the people is not just the background to the game, nor a device to drive on and introduce random shooting sections. It's the pivot around which the entire experience revolves. As Freeman makes a desperate bid to race through Earth's underground movement and send the aliens back to their dimension, every inch of ground you cover tells a story. There are no 'safe hubs' or markers in the script labelled 'insert big set-piece here', every step taken further enriches the game or endangers Freeman. The whole game is one giant set-piece, one massive adventure.

Even the 'cut-scenes' never detach you from the action, the gameplay seamlessly blending into face-to-face conversations with people, then back out the other side to continue the missions. There are surprises - quite literally at times - around every corner, and new discoveries and revelations with every minute that passes. The story is told with such fluency, and peppered with such crafty ingenuity, the whole experience washes over you in waves.

Keep your eyes peeled for the climatic battle with a gunship on the underside of a giant iron bridge. Once it's all over and you're left dangling above the sea a few hundred feet up, don't for one minute think you can sit around and catch your breath. You'll see what we mean...

Freeman is held in high regard by many in the resistance movement, and they are always eager to help him out with new weaponry. Then, of course, there are the shadowy figures that lurk on the fringes. As in the first game, the mysterious GMan can sometimes be seen watching you from afar - and just what does the creepy agent of Big Brother have in his briefcase this time? On the whole, though, if it's not wearing a gas mask or vomiting its own stomach at you, it's a friend.

One such friend is Alyx Vance, who not only looks cute in her hippy-scientist get-up, but also gives you the Gravity Gun, which, for the purposes of future generations, is now officially the coolest in-game item ever created. It can lift just about any reasonably sized, non-biological object into the air, and then throw it across the level. It's great for lobbing compressed air canisters into fires, hurling exploding barrels into enemies, chucking buzz-saw blades into the stomachs of aliens frisbee-style, or using wardrobes to block off doorways to prevent an attack. We actually had to tear a radiator from the wall at one point, and waltzed through a level armed with nothing else. It's a rare thing indeed to be able to make your way through a game with such a degree of freedom.

Besides the immensely pleasurable use of the Havok physics engine, everything else in the world obeys the laws of gravity, buoyancy, inertia, and so on. Bottles roll and smash, ropes swing, and crates tumble down stairs when you walk into them. When incidental aspects such as this - a pane of glass will shatter precisely where you hit it - work so perfectly, bigger moments can only be measured by the capacity they have to take your breath away.

AI is another example of just how finely Valve has honed its art. Throw a canister to distract an intelligent Combine soldier (the chaps in the gas masks) and the chances are he'll ignore it and zero straight in on you. However, do the same thing to an infected civilian stumbling about with a headcrab sucking at his skull, and it will lumber off to investigate the sound. Make too much noise, or shine your torch in the path of an enemy and they will see you. The AI can be brutally intelligent, but thankfully not without weaknesses. They don't all know about the powers of the Gravity Gun, which makes toppling a wardrobe on top of them, or flipping a car over to crush them, deeply satisfying.

Half-Life 2, were it just a collection of staggering action set-pieces and messing with physics, would still be one of the best games ever made, but it's so much more than that. The environments you work through are a vast mine of traps and conundrums, some of which are so large and devilish it's only when you've reached the end of a level that you discover the entire thing is one huge Mousetrap-style puzzle that requires more than just a gun to complete. You have to learn to use reasoning, patience and cunning to survive, not just be a dab hand at taking heads off with shotguns.

Half-Life 2 is the only game we can think of where such astounding violence is so perfectly balanced with measured thought. As if to reinforce the idea, puzzles never become dull, and they never sideline you into dead ends or act as time-fillers. They are perfect. It's this careful combination of the two game modes that makes Half-Life 2 not only a brilliant single-player experience on Xbox, but one of the best single-player games of all time.

Half-Life 2 was never envisioned as being a flag-capturing deathmatch frenzy, you see. Just because a game is played out in first person doesn't mean it must toe the line regarding multiplayer modes or Live play, and to be honest, Live will be the furthest thing from your mind once you're engaged in the frantic single-player experience.

You won't want to share the experience - and to have added a multitude of Live options would certainly have impacted upon Valve's ability to fit the game on a single disc. The game doesn't suffer too much from not having the multiplayer options of the PC version, though it is a shame there's no option to download any future episodes. Having said that, there are more than enough game modes within the actual single-player campaign to keep players happy.

The variety of gameplay is, as with so much of Half-Life 2, just another of its strengths. It can shift in an instant from being a creepy, nerve-shredding fight for survival among the shadowy ruins of a village, to frantic scrambles on dune buggies across the open countryside, while being bombed on all sides by ground-slamming attack choppers.

What with tanks smacking you around with heat-recognition smart bombs, zombies crawling half-dead through broken glass to attack you, or unseen snipers cutting the air with their blue laser targeting, just about every flavour of shooter is represented here, and with genuine style and panache. Creeping terror fan or trigger-happy commando - whatever category you fall into, you'll come away breathless and amazed.

Every turn, every tunnel, and every bullet fired offers something new. You'll play fetch with a giant robot dog and get strangled by a 13-foot-long tongue. You'll stop at a ruined cliffside house to juggle the cars in the car park, and while away an afternoon in an infested cemetery with a drunken Irish priest. It's a thing of beauty, from beginning to end. You'll barely have time to wonder how they did it, but Half-Life 2 is as perfect a game as you'll ever play. We're still picking our jaws off the floor. And if the 98%+ score hasn't convinced you, look out for our demo coming in 2006.

1. An intense, superbly scripted storyline sucks you in and will keep you there until you've played it, oh, at least ten times over.
2. The Gravity Gun is the coolest thing in videogame history. Forget every other weapon you've seen - this is the mama and the dada.
3. When you can see for miles and witness spectacles that have you grinning from ear to ear, you know you're onto a winner.
4. The pacing of the game is amazing. From minefields infested with bugs to open plains of scorched earth, you'll love the lot.

1. We can forgive the culling of any multiplayer but we would have liked to see an option to download future episodes like on PC.

Crafted with every kind of brilliance imaginable, this has to be played to be believed. Practically flawless gaming.