The player can send Fenix almost anywhere in the game environment that a real marine weighed down with body armor and weapons could go, including scrambling over rubble piles and smashing through doors. But if the player is smart, Fenix spends more time diving for cover than traveling. Gun battles are the heart of Gears of War, and the best way to defeat the Horde is to put Fenix behind a concrete barrier, stick his gun--and as little of his head as possible--around the edge, pick off the nearest Locust drones, then dash to another hiding place. But the drones, too, are using cover, which forces the player to think carefully about the chesslike geography of each firefight. Snap decisions are also required, since the Horde can switch to charging, retreating, or flanking maneuvers as the situation warrants.

Technically, Gears of War is a "third-person shooter": you have control over Fenix's movements and actions, but you don't see through his eyes. Rather, you watch him from behind, as if through a movie camera. That gives you a more visceral connection to the character, especially when your clumsiness with the controls gets him killed. (The Locusts literally blow him to pieces.) The third-person technique is put to more amusing effect when the player Fenix crouches and runs at the same time, a maneuver called the "roadie run." The camera bumps along behind him with a shaky movement that has led some gamers to nickname the maneuver the "CNN run."

Fenix's weapons are standard issue, except for his delightfully malevolent Lancer machine gun, which has a built-in chainsaw for close-quarters combat, and the Hammer of Dawn, a devastating satellite-based particle beam that can be activated when Fenix is under open sky. While many video games are devilishly hard to beat even at a beginner's difficulty level, these powerful weapons help Gears of War players of all levels make steady progress--as long as they don't mind being killed and returning to the last saved checkpoint every few minutes.

While I'm not a rabid gamer and haven't tested every title out there, I can honestly say that I have never played a more immersive, heart-racing, and pleasantly challenging game. Gears of War does for the first-person-shooter genre what HBO's The Sopranos did for gangster shows, leavening the inevitable violence with new drama and intelligence, along with a big dose of old-fashioned adrenaline. It also raises the bar for the rest of the industry. Competing game developers will now have to figure out how to make their universes more textured, realistic, and responsive, while at the same time giving players more freedom to do what comes naturally--and to invent their own strategies.

An earlier version of this story incorrectly stated that the PlayStation 3's output is limited to 720 lines of vertical resolution. In fact, it can play high-definition video with a full 1,080 lines of resolution. But on the PlayStation 3, games such as Resistance: Fall of Man that (like Gears of War) are produced with 720 lines of resolution are displayed at that same resolution, whereas the Xbox 360 contains a video-scaling chip called Ana that stretches 720-pixel images into HD-quality, 1,080-line images.