Halo 2, the long-awaited sequel to one of the most widely praised, most influential first-person shooters ever created, has a very tough act to follow. Fortunately, it's built on a foundation that's as strong as they come. The game's success was preordained--publisher Microsoft tallied more than 1.5 million Halo 2 preorders in the weeks leading up to the game's release, which demonstrates just how confident Halo's fans are in the sequel's quality. But how is it, really? The good news is, the sequel to the Xbox's defining action game is an absolutely superb, fully featured game, boasting an excellent presentation, a highly replayable campaign, and the greatest, most complete online multiplayer component in a console shooter yet. A surprisingly disappointing story and a fairly short single-player portion are noticeable shortcomings, but there's just so much breadth of content in Halo 2, and the action itself is so outstanding, that there can be no denying its quality. Overall, it's one of the very best action games available.

It's good to see you, Master Chief.

There are several reasons why the original Halo ranks up there with a very small number of other first-person shooters as one of the definitive games in the genre. For one thing, Halo succeeded at establishing a cohesive, memorable, and original science-fiction universe. For another, the Master Chief, Halo's cybernetic protagonist, made a great hero. A fearless, enigmatic man, the Chief could succeed where pure flesh-and-blood humans could not, and guiding him to victory against the alien menace known as the Covenant, as well as the parasitic creatures called the Flood, made for a gripping story and an intense and satisfying gameplay experience.

Halo's gameplay was amazing in that it seamlessly integrated top-notch first-person shooting with incredibly fun third-person vehicular sequences and outstanding friendly and enemy artificial intelligence. The game's subtle innovations--the tactical consequences of such things as having recharging energy shields, being able to carry only a couple of weapons at a time, the ability to throw powerful grenades in between shots, and the option of dishing out fierce melee attacks--also did a lot to differentiate Halo from other shooters, and proceeded to influence subsequent games. Halo's multiple, well-balanced difficulty settings, two-player cooperative campaign option, and assorted multiplayer modes also ensured that the game had tons of lasting appeal. All these factors contributed to the game's well-deserved success, and they're all back in Halo 2. For the most part, the sequel takes an "if it ain't broke, don't fix it" approach to its gameplay--everything that you loved about Halo's action is back in full effect here. At the same time, the handful of new additions in Halo 2 are well thought out and well implemented, enriching the gameplay and making it seem fresh but still familiar.

Everything that you maybe didn't love about Halo is pretty much back, too. Let's face it: Halo was an incredible game, but some aspects of it were relatively weak. Most notably, many players felt that the game's occasionally repetitive level designs undermined the action, such as when the Master Chief squared off against the Flood in the infamous Library level. Also, though the game's visuals were terrific in the heat of battle, Halo's cinematic cutscenes using the game's 3D engine left a lot to be desired--they looked decidedly rough when compared with the rest of the game. These shortcomings rear their heads again in Halo 2, at least during the game's campaign. Some of the in-engine cutscenes are kind of ugly, though they're much better than those of the original. Meanwhile, the action itself is as dynamic and intense as ever, to the point where it can be tons of fun to replay the same sequence over and over, since you'll find that the friendly and enemy forces you'll be battling with will never act quite the same way twice. However, Halo 2's campaign--though it features a number of memorable, spectacular set pieces--frequently boils down to straight-up run-and-gun corridor crawls, one after another.

Halo 2 plays much like its three-year-old predecessor, and the gameplay's just as fun and intense as ever. If it ain't broke, don't fix it.

All your attention tends to get concentrated on the action itself, partly because the action is just so good but also because there's often little of interest in the game's environments. The level design is quite striking at times--you'll find yourself stopping just to gaze at the architecture--but it's occasionally monotonous enough to be confusing. You'll sometimes wander aimlessly for a few minutes, unable to tell which way is forward and which way is backward, until you happen upon the next signs of enemy resistance. Basically, the campaign is still a linear series of shootouts, some of which are open-ended enough to afford you the ability to choose from multiple weapons or vehicles, and some of which are more rigid. If the Flood levels of Halo didn't bother you, then you probably won't mind the similar sequences in Halo 2. If you don't fondly recall those bits of the first game, though, you might find yourself frustrated that Halo 2 follows a similar formula.

Even the content of Halo 2's campaign isn't significantly different from that of the first game. Prepare to take on many of the same foes in many of the same types of situations and locales. Of course, the game does take you into some new territory and pits you against some new threats (such as some hard-to-hit flying enemies and an enormous spiderlike Covenant battle tank), and sure enough, these sequences turn out to be some of the best bits of the campaign. Early on, for instance, you'll be defending Earth itself from a Covenant assault, rampaging through the war-torn streets on foot, at the wheel (or the mounted turret) of a Warthog 4x4, or in the belly of a devastating Scorpion battle tank. All this is thrilling. Yet while it's hard to imagine a better setup for Halo 2's action than putting the fate of Earth's defense in your hands, the game turns out to have other intentions, and rather suddenly changes gears after just a few hours.