The noise level was rising, the body count was mounting and the 13 Marines sitting in front of computer screens in a dark room here seemed briefly to have forgotten that the urban combat mission was just a video game.
"Sniper on the roof! Sniper on the roof!" shouted Justin J. Taylor, a corporal leading Fire Team 2, half jumping out of his chair as his eyes stayed glued to the monitor.
"Where? Where? Where?" demanded a comrade in Fire Team 3.
"I'm shot," came the despairing reply. "I can't see anything."
As the military embraces electronic games as a training tool, a growing number of soldiers are fighting in a virtual Iraq war even as they remain stateside. For many soldiers, the increasingly realistic simulations often seem like the closest thing to being in combat.
"It gives you a sense of reality," Taylor said. "You get that nervous feeling: Do I really want to go around the corner or not? You want to complete the job you've been assigned to do."
Recent recruits who grew up on popular commercial games like Half-Life, Counterstrike and Quake 3 have a natural affinity for the training games, many of which are adapted by the military from the retail versions. Some military officials are enthusiastic about the benefits of running troops through the exercises at minimal expense.
But as video war games gain popularity throughout the armed forces, some military trainers worry that the more the games seem like war, the more war may start to seem like a game. As the technology gets better, they say, it becomes a more powerful tool and a more dangerous one.
The debate over the use of computer simulations large and small was sharpened when General William S. Wallace, the commander of the Army V Corps based in Kuwait, remarked that the guerrilla-style resistance of Iraqi militia groups made for an enemy that was "different from the one we war-gamed against."
The current situation in Iraq, some critics say, may highlight the problem of depending too much on virtual realities for training. They argue that military leaders can become too enmeshed in a gaming scenario to allow for what is actually happening.
Wallace's forces directed a computerized dress rehearsal for the Iraqi invasion with several hundred Army, Marine and Air Force officers last January in Grafenwoehr, Germany. The command center led by General Tommy Franks of the Army conducted its own computer simulation, Operation Internal Look, last December in Qatar.
"You can get so habituated to the gamed reality that the real reality, what's on the ground now, is thought to be artificial," said James Der Derian, principal investigator of the Information Technology War and Peace Project, a nonprofit group that studies the impact of technology on global politics. "If the war doesn't go according to the game, you just keep trying to make it fit."
Computer-simulated war games, like the one hijacked by Matthew Broderick's hacker character in the 1983 film WarGames, have long been used by high-ranking military officers to test large-scale maneuvers that cannot easily be replicated in the real world.
What is new is both the way the games are filtering down through the ranks to the lowest level of infantry soldiers, and the broader vision that is being contemplated for them at the highest levels of the Pentagon.
"These kids have grown up with this technology from birth," said Dan Gardner, director of readiness and training policy and programs in the office of the secretary of defense. "If there are tools that are less painful than reading through a book and can give them a better sense of what it might be like, we need to use them."