AUBURN – No one could touch them.

Not with grenades. Not with automatic weapons. Not with sneak attacks.

James and Chris Bellman – brothers-in-arms on screen and mop-haired teenage brothers in real life – always seemed to know when, where and how the video-game enemy was coming. And they’d get there first.

“We like being the best,” said James, 18.

They’d proven themselves once, beating 30 other two-man teams at an August tournament sponsored by Bull Moose and Flagship Cinemas.

On Saturday, they defended their title.

For an hour at Flagship Cinemas in Auburn, 10 young men vied for small prizes and the right to call themselves the best Halo 3 players in the area.

A multi-player, first-person shooter game, Halo 3 is among the most popular video games in the world. It grossed $170 million in its first day of sales last fall, despite an M rating (for blood, gore, mild language and violence) that restricted it to older teenagers and adults.

The game’s storyline: Defend humanity in a 26th-century galactic war with aliens.

The goal: Kill as many enemies as possible.

In Saturday’s tournament, “the enemy” was the other two-man team, red vs. blue. Each kill was a point. Most points wins.

“Come, play, win some money. Why not?” said Jake Teich, 20, of Lewiston.

The 35-foot movie screen split into four sections to allow each player his own point of view. As a single-elimination tournament, the winner of each five- or 10-minute round would progress to the next.

At exactly 3 p.m., the theater started vibrating with the boom of explosions and the tat-a-tat-tat of automatic weapon fire.

Some of the players were hard-core gamers who played several hours a day. Others were virtual novices, at the tournament to have a little fun for the $8 entrance fee.

Anthony Craven, 16, and Nicholas Sylvester, 15, fell somewhere in between. They drove up from Strafford, N.H., but they hadn’t been able to practice much beforehand. Craven’s little brother lost the battery pack for his game controller.

“We might get second (place),” said Craven, his words nearly lost in the resounding boom that heralded another point for the Bellman brothers in an early round. “I don’t think we’ve got a chance against these guys.”

It turned out they didn’t.

James and Chris Bellman beat them in the next round, scoring the first point just seconds into it. The Bellmans chattered as they played, urging each other to “watch out” or “go ahead,” even when it wasn’t quite clear to anyone else what the brothers wanted each other to watch out for or go ahead with.

“We’ve been playing each other for, like, as long as I can remember,” said Chris, 15, of Mexico before the game.

“Yeah, the chemistry’s good,” said James of South Paris. “We know each other’s moves.”

That chemistry made them unbeatable straight through the last round, when they met up with Teich and his friend, John Fournier, also 20 and of Lewiston. The two sides hunted each other, and the Bellmans died more often – and more spectacularly – than in any other round.

But they still won.

Second- and third-place winners received Bull Moose gift certificates and movie tickets. The brothers split $50 for first place.

“We’re unstoppable, I guess,” said Chris with a small shrug and a grin.