San Francisco (CNN) -- Comparing the "Gears of War" video games, with their alien firefights and gory chain-saw scenes, to "The Lord of the Rings" might seem a bit far-fetched.

But that's the parallel Cliff Bleszinksi is going with for his third-person shooter game franchise.

As the design director for Epic Games, Bleszinksi is a creative force driving the "Gears" franchise to bow out gracefully. "Gears of War 3," which publisher Microsoft says will hit stores September 20, will be the last game in the hit series, executives say.

Hoping to achieve Hollywood's most coveted but often elusive goal -- ending a trilogy on a high note -- Bleszinksi evokes George Lucas and Peter Jackson in discussions of the game. But he'll have to channel his passions for Hollywood cinematics into the game for now because the long-in-development "Gears of War" movie won't be made anytime soon.

"Gears of War," about elite soldiers battling aliens on a fictional planet, has been a big seller since the first game debuted as an exclusive Xbox 360 title in 2006. A sequel followed in 2008, and developers at Epic Games have long wanted to cap the series with a third game.

"Let the game stand alone as its own sort of 'Lord of Rings' trilogy," Bleszinksi said in a recent interview.

To avoid disappointing, Bleszinksi and his cohorts convinced Microsoft Game Studios, the exclusive publisher of the "Gears of War" games, to delay the final installment past the planned April launch window, which the companies had announced a year in advance.

That bought Epic the time to polish the story-driven mode, which allows four people to play simultaneously, and flesh out what has become the longest plot of any game the developer has ever made, executives say.

In exchange for the extra development time, Epic is crafting a beta program that will be made available to Xbox subscribers in April, around the time of the original planned launch for the game. That sneak-peek version, designed for competitive online play, will include three distinct modes that can span four levels, said Rod Fergusson, Epic's executive producer for the "Gears of War" franchise.

"With that extra six months ... we were able to create this beta; we were able to put all that polish into the campaign," Fergusson said. "So it's going to be the best one ever. And that's really how we want to go out with this franchise."

Microsoft is no less enthusiastic. The two previous games combined have sold more than 12 million copies.

" 'Gears of War' is going to be the biggest game of 2011," said Kevin Unangst, a senior director for Microsoft's game publishing arm. "It's going to be a phenomenal release for us."

Though Epic is hanging up its Boomshot grenade launchers from the game, authors and comic book artists are keeping the "GoW" spirit alive. Executives say they plan to encourage these types of extensions of the storyline into other media.

One adaptation that's been a long time coming is a New Line Cinema movie based on the series. Time Warner owns New Line, along with CNN.

The project has gone through a number of revisions, recastings and, last year, a budget cut. "Underworld" director Len Wiseman has scaled back his involvement with the "Gears of War" movie and has been turning his attention to other films, according to a report in the Los Angeles Times.

"The 'Gears' movie has been in development for quite some time, and I can tell you it's been a heck of a learning experience," Bleszinksi said. "Making a video game movie -- one that doesn't suck -- is a Herculean task, and it's something that could take years to come."

New Line originally had budgeted $100 million for the epic action film, but producers dialed that back to about $60 million, Bleszinksi said.

Studio executives are looking at "District 9," the relatively low-budget science-fiction flick directed by Neill Blomkamp and produced by Jackson, as a model for "Gears of War," Bleszinksi said. That 2009 movie cost about $30 million to make and has grossed $210 million.

"They kind of went through the bean-counting machine of Hollywood" to save money on the project, Bleszinksi said. "Then, if it does well, we can blow it out with a sequel."

New Line determined a "Gears" movie would need to be gory, which would earn it an R rating and put it out of reach of many young gamers eager to see the series on the big screen, Bleszinksi said.

"If we show up at Comic-Con, and there's not chain saws and blood, the fans will tear us limb to limb," he said. "We're not going to release a movie that sucks."

A seemingly less optimistic Fergusson said: "As long as it gets made, I'll be happy."

And don't count out future "Gears of War" games, either. Epic's leadership left the door open for bringing the series back someday.

"If we do another 'Gears' in the future, let's have some wiggle room. It's a big universe. There's lots of other things we could do. Maybe it'll be a prequel, who knows," Bleszinksi said. "In Hollywood, they say the last sequel is the one that fails to make money."