MESQUITE, Texas — Marty Stratton has already blasted dozens of flame-tossing imps, flying skulls and other nightmarish demons from another dimension. But more keep spawning in flashes of yellow light.

"This is where it really starts getting scary," he says upon entering a new level of "Doom 3" where massive hell knights lob deadly balls of energy against a backdrop of shimmering lava pools and torches made of corpses. "I don't know how many times I've been through hell, but it just freaks me out."

Four years after setting out to remake one of the most popular and violent video games ever, Stratton and the rest of the crew at id Software Inc. are finally done with their latest vision.

"We're a bit nervous. It's like raising a child and you send them out into the world," said Tim Willits, one of the game's designers.

"Doom 3" hits store shelves today, though there were reports of some retailers breaking a midnight sales embargo and of pirated copies already being distributed for free on the Internet.

The $55 sequel typifies the first-person shooter genre id pioneered in the early 1990s with the original "Doom," "Quake" and "Wolfenstein 3D": Gamers run and gun through hordes of monsters or other enemies in three dimensions.

With each release, the visuals, sound and other effects have improved. "Doom 3" is by far the most realistic and looks nearly equal to animated films like "Shrek 2."

In "Doom 3" you are a marine on a martian outpost that becomes a gateway to hell after a series of top secret experiments involving ancient alien artifacts. With shotguns, rocket launchers, lasers and grenades, you alone must fend off a menagerie of beasts and possessed base workers.

It's a familiar formula that's served the tiny developer well. While some have decried id's games as overly violent, the company has sold millions of copies of one gory hit after another.

In turn, the games have spawned legions of loyal fans. By the thousands, gamers of all ages flock to "QuakeCon," an annual Texas gathering paid for by id where like-minded players meet and fight each other online.

Along with "Half-Life 2," "Doom 3" is one of the most anticipated games this year, said Greg Kasavin, executive editor of the review Web site GameSpot.com.

"It represents the next technological leap by id Software — a developer that's remained on the forefront of computer graphics and computer game technology for more than a decade," he said.