There are video games, and then there's Halo. For millions of people around the world, the science fiction FPS is the reason they play games. It's the reason they bought an Xbox. It's the reason they signed up to Xbox Live. Master Chief is their hero, a modern day icon for a modern day generation.

And there's a very good reason why. Halo: Combat Evolved and Halo 2 were fantastic FPS games with some of the greatest multiplayer ever to grace a console. But this brings with it problems. Just imagine the pressure on developer Bungie for Halo 3. Millions of gamers, all over the world, each and every one carrying with them their own reasons for loving the game, their own unforgettable experiences with friends on split-screen or on Xbox Live. And now, with Halo 3, they want new, better, more intense, more action-packed, more emotional and more epic experiences with Master Chief, the super-soldier they have followed to the ends of the galaxy and back for nearly six years, than ever before. How bad would it hurt if Halo 3 didn't live up to those lofty, and, if we're honest, unreasonable, expectations? Pretty damn bad.

But don't worry. We can finally end the heart-ache, the anticipation and the unbearable need to find out for yourself. Halo 3 is everything we hoped it would be, and much, much, more.

We've had the game in our hands for five days now, and in that time we've busted it wide open. We've finished the campaign and seen the final twists in the story arc that began with such a bang back with Halo: Combat Evolved in 2001. We've put more hours than we care to admit into the multiplayer, getting our hands on every weapon, every vehicle, and every piece of equipment the packed disk has to offer. We've saved films of our battles, watched them over and over from new, hilarious angles, and we've even made our own take on maps with the new Forge mode (more on that later). It's been a tiring but exhilarating five days, and not for a moment were we ungrateful.

So let us begin where Halo 2 left off, a refresher for those of you who haven't touched the campaign in the last game for a while. The Covenant has come to Earth, looking for a way to activate the Halo rings, built long ago by the mysterious Forerunners. The Elites, led by the Arbiter, the other playable character from Halo 2, have changed sides and left the Covenant after revealing Truth (the religious leader of the Covenant) as a liar. The Halo rings won't actually bring about the Great Journey; they'll bring about the end of the Flood (remember them?) and, at the same time, the universe.

The last thing we saw was Master Chief saying he was "finishing the fight" while falling to Earth on a Forerunner ship. Millions of gamers across the globe collectively scratched their heads. "Is that it?" they asked. Perhaps now we can finally admit that Halo 2's campaign was disappointing. And in the same paragraph, we can finally reveal that Halo 3's campaign is everything but.

We're being very careful not to include any spoilers in this review. But what we will say is that it's not long after Master Chief gets up from his landing that he's in the thick of the action. The first level is a fairly slow-paced affair, reminiscent of the opening assault in Arnie action flick The Predator, and is clearly designed to ease newcomers into the game. But it also serves as a prime example of how improved the graphics are. You begin in a jungle-like environment, full of almost photorealistic trees, swaying branches and foliage that reacts when you move through it. There are loads of gorgeous little touches that force you to stop and take notice, like the sun blinding you for half a second before your eyes adjust, Covenant Phantoms cruising overhead, Brutes manhandling Human soldiers on ridges away in the distance. You'll find yourself blasting your way out of Human bases, driving across abandoned freeways in Warthogs and making assaults on Covenent held structures, before the story takes its first twist.

We know what we'll be playing for the next few years

It's certainly next-gen stuff, but Halo 3 doesn't have the best graphics we've ever seen. There are some things we noticed that we weren't massively impressed by. For one, the water effects look merely average. The foliage isn't as impressive as Crysis' will be (assuming you've got a PC from the future), when it rains it isn't spellbinding and during cutscenes we noticed the odd character whose eyes did strange things. Take 2´s recent critically-acclaimed hit BioShock has more immediately stunning graphics, and indeed 2006's Gears of War trumps Halo 3 in the jaw-dropping adrenaline-pumping action category. But what must be remembered is that Halo 3 is a completely different game. Its levels are massive, on a scale greater than either of the previous two iterations. With levels this huge, and with so many enemies targeting "the Demon" at the same time, it's hard to achieve the same level of graphical splendour as a corridor shooter, which BioShock is in essence. While it's an impressive leap from Halo 2, the graphics won't convince those doubters who have seen screenshots and video of the multiplayer beta and thought "this is just Halo 2.5" to change their mind.

What we will shout about until the cows come home is how the game feels to play. As it has been throughout the series, you push forward through firefight after firefight and checkpoint after checkpoint, the pace effortlessly switching from tense and disturbing internal sections to vehicle-based assaults across miles of open ground. Each level will take you between an hour and an hour-and-a-half depending on the difficulty and your skill level, and has about three special checkpoints that you can start over from once you've quit out of the campaign. With the Elites on your side, alien forces are headed up by the promoted Brutes, who pose an altogether different threat. You'll find yourself facing them in packs, often with supporting Grunts and Jackals. The Brutes will sometimes be following orders from a chief who wields the devastating Gravity Hammer, which immediately goes down as one of the most destructive FPS weapons of all time. The Brutes are more savage than the Elites were in Halo 2, taking a lot of hits to go down. They'll even drop their weapons and just charge at you once you've shot them up a bit. You'll come to loathe sniping Jackals and, once again, kill the pack leader, and the Grunts scatter. Some of the little buggers will go kamikaze and run at you with primed plasma grenades. Watch out for those.

Enemies will use the new hardware almost as much as you will

The AI is certainly a step up from Halo 2, although not entirely convincing. Bungie has mentioned the "pack mentality" before, and you can see what they're talking about. Brutes will stick together and tend to hang back while Grunts and Jackals do their dirty work. There's the odd occasion, usually experienced when playing on the harder difficulties, where you'll be impressed with how the Brutes have sniffed you out of cover, but most of the time being patient and not rushing in will do the trick. On the Human side, we found our AI team-mates to be much more use than in the previous games. When playing single-player the computer controls the Arbiter, and he's one hell of a shot.

Did we mention the Gravity Hammer? It deserves special attention simply because it's so sweet to use. It's not long into the game before you get to use one, and the first time you do it's a guaranteed jaw-dropper. It's a melee-based weapon that you swing like an axe, impacting a spectacular blow (including cool sci-fi sound and gravity distortion effect) that can knock rockets out of the sky, smash speeding vehicles into smithereens and sends enemies flying off into the distance. It's also a great way to show off the Havok physics engine. Enemies hiding behind crates and defensive positions have no cover against the Gravity Hammer. It makes you feel invincible, and when you pick one up you invariably charge into packs of Brutes swinging like a crazed lunatic. Think Sauron in the opening scene of Lord of the Rings.

Another great addition to Master Chief's arsenal is the ability to tear turrets from the ground and use them to tear up the enemy. This switches you to a Gears of War-esque over the shoulder view while you slowly lumber around unpacking tens of devastating rounds a second into anything that moves. It's great fun, although it does leave you exposed if you're facing multiple enemies, and again brings to mind Arnie, this time in sci-fi classic The Terminator 2.

The Assault Rifle makes a welcome return following its hiatus during Halo 2. Bungie has said that it felt dual wielding in the last game stopped a lot of players using grenades, so it has changed the weapon balancing drastically. We found the Assault Rifle to be our most used weapon through the campaign. The spray is very powerful at medium range, it's great used as a melee weapon and the clip tends to last. There are plenty of other new toys to play around with too, including the Spartan Laser, which pops up sporadically throughout the campaign and the flamethrower, which you use like a turret. The Covenant has some really cool new weapons that we had a lot of fun using, too. The Brute Spiker is kind of like the Covenant version of the Submachine Gun. The Mauler is like a Brute shotgun. A great combo is to dual-wield one of each, loosening up enemies mid-distance with the Spiker before mopping them up with the Mauler. There are just so many weapons to choose from that it's safe to say that Halo 3 is the most destructive Halo yet.

Supplementing the weapon/grenade dynamic we've all become so used to is the addition of equipment. It's because of the equipment that the default control system has undergone somewhat of an overhaul. X now deploys your equipment, which you'll get to try out fairly early on in the game. The first you'll probably see is the Bubble Shield, a small defensive dome that stops enemy fire from getting in and your fire from getting out. It's really useful when the heat is on and your shield is down, but you're not the only one clued up. The Covenent has access to equipment too, and there's nothing worse than seeing a Brute lay down a Bubble Shield when you're under the cosh. There's tonnes of equipment out there, including trip mines, energy drains, flares and grav lifts. Some of the really cool ones we didn't come across until late in the game. We'll let you discover those for yourself.

For some, it's not about the weapons, nor the new equipment. It is, and always will be, about Halo's vehicles. It's here that we really have to bow down and praise Bungie, because they've added some seriously cool vehicles to Halo 3. On the ground, our new favourite has to be the Chopper, a one-man Brute vehicle with a large front wheel and auto-cannons. It's like the love child of Mad Max and Ben Hur, and just about beats power sliding your way through bunches of Grunts on the classic Warthog. In the air, the Covenant Ghost has a new rival - the one-man Hornet. When we saw the vehicles for the first time, it was a real OMG! moment. Once you get used to the controls, the Hornets become absolutely savage fun to use. We won't spoil it for you, but rest assured there are moments in the campaign where you get to use the Hornets in extremely cool circumstances.

You can rip these up and walk around with them

Halo 3 isn't all about causing havoc and beating down Brutes though. There are also little asides to the main campaign proper that make it worth taking your time as you battle your way through the game. At one stage we came across a Human soldier who was having an argument with another soldier over a password given out during a staff meeting. The two soldiers had this hilarious stand off where one wouldn't open a door, despite the other constantly moaning and banging. This was completely off the beaten track and something we wouldn't have noticed had we simply powered through the game, seeking out check point after check point.

That's another thing you'll notice about Halo 3's campaign. There's more dialogue than ever before. Soldiers will constantly be talking while battles are taking place and during down time. The enemies are chatterboxes too. In one area, we surprised a Grunt who said: "You don't look like you're here to help!" In another area, we stumbled upon a Brute leader giving out search instructions to his subordinates. It all adds to the feeling that you really are stuck in an intergalactic war, fighting for the lives of real soldiers and against a determined, intelligent enemy.

The five days we spent with the game, incidentally, was more than enough time to complete the campaign. Playing co-operatively on the normal difficulty setting, it took us about 15 hours to work our way through to the end, although we were stopping at every opportunity to admire the scenery. Heroic is about right for an experienced Halo player. But you'll definitely want to go two-player co-op, or even make use of the new four-player campaign co-op either on XBL or via system link (only two players can play campaign on one console) for the legendary difficulty setting. This, admittedly, isn't a feature we've been able to try out as of yet, but we'll get you a report as soon as we do.

Dual wielding returns, but a single-weapon plus grenades is still a good option.

So, having seen the campaign through to the end, how does it stack up against the competition? There's a lot about the campaign we can't talk about, but what we will say is that the game has that unmistakeable, sci-fi epicness that has become a trademark of the series, and some very special Halo characters make a welcome (and not so welcome) return. The storyline can be a tad difficult to follow at times, and we sometimes found it hard to make out what characters were saying during cut-scenes. The mission environments aren't hugely varied (Halo: Combat Evolved was criticised for recycling the same areas over and over again), but it's full of fabulously heroic science fiction twists and turns, and definitely won't disappoint Halo fans. The fact that newcomers might struggle to understand why they're doing what they're doing just serves to highlight Bungie's approach to the game. It feels like it's for those of us who have been there all along. No tedious training mission, no effort to justify itself, just the confidence to do what it does best - cracking firefights, spectacular vehicular combat and fabulous fun. While BioShock might have had the more absorbing and clever storyline, we were much more satisfied when we finished Halo 3.

4-player co-op and Forge just add to the brilliance

As far as fun goes, Halo 3 is certainly a more enjoyable play through than Halo 2, if only because the transition from weapon combat to vehicle combat is smoother and, well, there's just more to play with. There was more than one occasion where we thought "this is just like the original Halo". While some might welcome this back to basics approach, others might criticise the developers for a lack of new ideas. Did we feel as completely blown away as we did by Halo: Combat Evolved? Probably not, although the final couple of hours are the most impressive graphically and completely engrossing, where BioShock went downhill fast towards the end. But it's a close run thing. Campaign verdict? Better than Halo 2 by a plasma grenade throw, but just behind Halo: Combat Evolved by the skin of Master Chief's teeth (if the big guy has any).

With the campaign sorted, we turned our attention to the multiplayer, and it's here that Halo 3 again demonstrates its confidence in its foundations. As many people commented after playing the multiplayer beta, Halo 3 multiplayer is fundamentally the same as before, apart from new weapons, vehicles and maps. The addition of equipment spices things up a little, but doesn't revolutionise the combat. Truth be told, it didn't need an overhaul, just a lick of next-gen paint, and that's exactly what the game has got.

The intensity and thrills of the multiplayer are hard to beat anywhere in gaming. That's why Halo 2, despite its less than impressive storyline, continued to be the most played game on XBL for so long. Expect Halo 3 to take over from Gears of War at the top of the online tree, and expect it to stay there for a very long time. Indeed many Halo fans will completely bypass the campaign and head straight for the multiplayer, such is its appeal. There aren't many games that get the hairs on the back of your neck reaching for the sky, but your first Halo 3 multiplayer game with friends will certainly do that.

While you can't do four-player campaign co-op on one console, you can in multiplayer, and it was this mode we pumped most time into. As a result, we haven't yet got the most out of the maps that are designed for more players (the game supports 16 at most), like Valhalla, and Sand Trap, but once the XBL servers are up and running following the game's official release, we'll bring you a full report.

Halo 3 deserves a 10 because it's the most complete FPS experience ever released

Of the new maps, we had most fun four-player on Narrows, a map designed for two to six players. As the name suggests, it's a long, narrow installation in the sky, with two grav lifts on either side. We just ended up flying through the sky, trying to melee each other in mid air. Classic Halo hilarity.

Multiplayer Halo 3 will soon become Xbox LIVE's biggest offering

Equipment can certainly get you out of a lot of trouble (the bubble shield is a Spartan's greatest friend), but it doesn't change the dynamic of the game. It simply adds a dash extra to the already delectable mix. Experienced players will instantly feel at home, employing similar tactics and skills as before. It'll take you a while to instantly recognise the various equipment symbols that pop up on the top left of the HUD, but once you do, deploying them will become second nature. If you were good at Halo 2, you'll be good at Halo 3. Melee is much improved, as are grenades. While dual wielding proved so effective in Halo 2, you'll almost always want one hand free for a grenade lob and a sneaky assassination when the heat is on.

There really isn't much more you can say about the multiplayer on Halo 3. It's certainly the most complete of the three games. It's bigger, badder and more destructive, but it's not that different. If you think about it, that's all we really wanted, and needed. There have been a few criticisms post multiplayer beta that there's nothing new worth getting excited about. But this misses the point. You should get excited about it, because, even after all this time, there isn't a better FPS multiplayer experience out there. A familiar experience of course, but great nonetheless.

If Bungie had simply closed the can on the game there, it would have been enough to satisfy Halo's fanatical horde of fans. But it didn't. Bungie has gone one step further with Halo 3, and, indeed with the FPS genre as a whole, by adding the most comprehensive package of community features ever seen in a videogame. The first is the Theatre mode, which allows you to look back at your multiplayer and campaign games from the point of view of a free roaming camera (accessed with the Y button). Everything you do is automatically saved to the 360's hard disk (we found most of our multiplayer games were between one and two MB). You can pause, fast forward, view over the shoulder cam, switch between players and even swirl the camera 360 degrees while in slow-mo ala The Matrix. More impressive is the ability to save screenshots and clips, then share them with your friends via XBL. So you can pause the game right at the point where you fired a rocket up your mate's ass, save a screenshot, upload it to Bungie.net then download it as your screensaver. Sweet.

The potential here is obvious. The guys behind comedy machinima Red vs Blue will be dribbling with glee. Clans will also have their trigger fingers poised, as they'll be able to see exactly why they just got owned in a replay. The Theatre is a wonderful addition to the game, and unfortunately for other developers raises the FPS bar even higher.

Then there's the Forge. We have to admit, when we first heard about the Forge, we were a bit confused. Even when I heard a Bungie podcast explaining the thing, I wasn't convinced the Bungie guys were even sure what it was. This, in a funny way, is exactly what it's all about. It's a real-time map making game mode that we just can't predict the outcome of. In Forge mode, pressing up on the d-pad will turn you into this omnipotent map creator which looks like 343 Guilty Spark from previous Halo games. You fly around dropping vehicles, weapons, equipment and crates onto the map bought with a set amount of dollars. You can change spawn points, set teleporters and grav lifts, dump fusion coils and pretty much mess about with anything in any given map, bar the actual environments themselves.

There's two ways to look at the Forge. One, as a map editor and two, as a multiplayer game mode in itself, where you can instantly switch between Forge mode and normal mode, creating cover for team-mates, dropping tanks on enemies and, well, anything you can come up with. As a map editor it certainly works well, and expect to see Bungie featuring some of the better community-made ones. But as a multiplayer mode we're not so sure. It certainly takes a while to wrap your head around the fact that you can change into a flying ball when you're being hit and give yourself a Scorpion tank. We're not sure how popular it will be on XBL and with friends in your front room. Our Forge games descended into chaos, putting our differences aside to pile vehicles onto grav lifts with the odd fusion coil added for good measure. Then we fired rockets just to see what happened.

So, finally, onto the review score. Despite Halo 3 being more combat evolved than combat revolutionised, Halo 3 deserves a 10 because it's the most complete FPS experience ever released. We can sum up why Halo is great with one, simple anecdote. You may have read last week on the site that we managed to snag a retail copy of the game from Argos. It sparked something I've never experienced before in gaming. A flood of instant messages, emails and texts followed. I got calls from friends and family asking to come over and play the game. And when they did, when that unmistakable music kicked in, when the Bungie logo flashed across the HD LCD, I could feel the excitement in the air like the after effects of a destroyed fusion coil. I can't remember the last time having a game in my possession before official release did that.

Halo 3 transcends video games. It is a global entertainment experience. Just as Lord of the Rings: Return of the King and Spiderman 3 brought to a close two of the most lucrative and epic film trilogies of all time, Halo 3 brings to a close perhaps the most complete, engaging and downright fun video game trilogy of all time. There is absolutely no way any Halo fan will be disappointed by this game. You better believe the Chief has triumphantly returned. Now buy the game, cock the Assault Rifle, and finish the fight.