The hallowed halls of id Software are notoriously difficult to infiltrate. As the revered creators of Doom and Quake, their offices are perpetually locked down and visitors are rarely permitted. So imagine our surprise when we were invited deep into their Mesquite, Texas, headquarters to be the very first in the world to play Return To Castle Wolfenstein: Tides Of War. It's the update of id's decade-old PC classic that's been pumped up by Nerve Software and unleashed on the Xbox with a slew of new goodies.

Suffice to say, we came away beaming with excitement, and we even managed to bring back an exclusive two-level playable demo for you to try on this month's Game Disc.

From the beginning, it goes like this: You are B. J. Blazkowicz (pronounced "Blaz-co-witz"), an American agent in the Office of Secret Actions. The OSA is a programme co-opted by the U.S. and Britain whose purpose involves intelligence gathering and covert operations. B.J. and British operative Agent One are sent in to investigate some strange and undoubtedly evil happenings deep in the heart of East Germany circa World War II. What the hell are the Nazis up to? What are they capable of?

The search for answers begins with an all-new prologue that introduces Agent One as he guides B.J. through the streets of Egypt.

At the conclusion of the initial chapter, the pair are captured and transferred to Castle Wolfenstein. The total PC single-player game was already a 15-20 hour affair, and you can expect an additional three-five hours of gaming sweetness at the onset of the action on the Xbox. And if you haven't played the PC version, you won't notice a thing. The prologue flows seamlessly into the rest of the story arc.

As the story unfolds, Wolfenstein's most obvious eye-catcher is its presentation. The game gleams with a polish not often found this side of Splinter Cell. Throughout the adventure, an abundance of cutscenes helps the narrative flow. There are dozens of scenes spliced between levels, and all are coated in a triple-A-quality sheen. Lip-synching is excellent, and the engine used to power both the cutscenes and the game itself is a work of art. The engine is the latest iteration of id's Quake technology, which is generally regarded as the best in the business.

Music is dramatic and dynamic, cueing in when the action intensifies. Although it can get repetitive, as B.J. frequently finds himself in tense, drama-filled situations, the tunes nonetheless have an epic quality to them that ups the experience. The sound is fantastic - idle Nazi guards have (often funny) conversations. The weapons give an authoritative, resounding oomph, and enemies writhe in agonising pain when dying.

What ultimately matters most, however, isn't how Wolfenstein looks or sounds, but how it plays. Thankfully, there is no doubt about its greatness. From start to finish it's an epic, gripping, cinematic adventure filled with questions. It's obvious that the Nazis are evil, but what exactly are they looking for? How far does their devout belief in the occult go? Along the way, all the riddles are solved and B.J.'s true challenge comes in survival. Once he gets in deep with the Nazis, it's obvious that the only way out is to power his way through.

There are well over a dozen weapons in Blazkowicz's arsenal, each with a deadly speciality. The weapons in general are, in fact, a highlight of the game. Each is carefully balanced and possesses its own strengths and weaknesses. There truly is a time and a place for each one. In a throwback to the old days of gaming, there are even secret areas, chockfull of health, ammo and power-ups.

B.J. won't always be running and gunning, however. In addition to blasting his way through Nazi Germany, sharp shooting and stealth-oriented challenges also await our hero. In a level near the middle of the game, for example, B.J. must escort an Allied tank through the burned-out streets of a German village.

Precise use of the sniper rifle is critical. Later, the brawny American has to sneak his way through the Nazi-infested Paderborn Village, hunt down five Third Reich generals, and assassinate each one, all without alerting a soul. Backstabbing with the dagger and using the game's lean left and right function is key.

Throughout the entire ordeal, there is a wealth of opposition to hinder B.J.'s progress. Run-of-the-mill Nazi Troops, sexy but deadly Elite Guards, disturbing Nazi BioDogs, biomechanical Super Soldiers, legless Lopers, and even a few big boss encounters all stand between B.J. and victory.

Make no mistake - if these baddies sound tough, it's because they are. The solo campaign gets downright nasty at points, even on the default difficulty. Along with conservative, yet effective use of booby traps, the AI is very good, and they're most often packing the same impressive stockpile of weaponry as B.J. (rocket launcher and Venom chain gun-toting foes are particularly taxing).

The game leaves auto-aim on by default, but it's a subtle helper that doesn't wander toward a nearby target quite as liberally as many other first-person shooters. Headshots are in full force here, though, so cranial connections will cause a lot more damage.

While the single-player mode is a spectacle on its own, the unsung star of this war is unquestionably the multiplayer game. First, the co-op play, which can be summed up in two words: Woohoo!... almost. It's an absolute blast to fight through the campaign, with you as B.J. and a friend as Agent One. However, there's no System Link or Xbox Live support for co-op, so it's one screen for both players or bust.

On the competitive side of the coin, the game shines. In fact, we can pay Tides Of War no greater compliment than to say that it is the definitive Xbox Live experience of the service's short history. Its sheer volume of teamplay-focused goodness eclipses even Ghost Recon, an office favourite. There are a whopping sixteen multiplayer maps out of the box, no fewer than four game types, and four classes to play as. The Xbox Live Voice Communicator again sparkles, enabling instant, crystal-clear communication between team-mates. Nerve has even added a simple but godsend of a feature: a small speaker icon appears over the head of the player that's talking. Yes! The balance between classes is also superb. Each needs the other and lone-wolfing it is not effective.

Even if you've played the PC version of the game, there's a lot here you haven't seen. In fact, there's so much goodness packed into Tides Of War that it's impossible not to find something to like. Separately, the single-player and multiplayer components are worth buying. Together in one box, they make Return To Castle Wolfenstein an incredible package.

1. Graphics are great!
2. Co-op play is ace
3. Captivating solo campaign
4. Multiplay rocks!

1. Music is repetitive
2. Co-op play only in split-screen

Power
Sleek and polished. Cutscenes look great. The id technology is razor sharp and painstakingly refined.

Style
It does everything so well that it's impossible to dislike. Weapons effects are lush, too.

Immersion
The story is tightly woven into the adventure and the presentation is good enough to pull you in.

Lifespan
Online play via Xbox Live guarantees this title a long and very happy life.

Summary
A cracking action shooter that is superb in single-player and provides outstanding team play experiences on Xbox Live.