The midafternoon sun beams through the front door of Netherworld Haunted House in Norcross. Yeah, vampires may still be crashing in their coffins, but Ben Armstrong is a step ahead of these creatures of the night.

The co-founder of Netherworld is busy putting the finishing touches on the award-winning haunt’s latest installment. All of the lights are on, and the mechanical effects are running full blast to see what’s working and what’s not. Robotic snakes slither, faux smoke wafts through the air, giant animatronic monsters rage from above.

It’s difficult to hear Armstrong over all of the terror-tinged noise ringing through Netherworld’s winding halls. But the boyish grin stretching across his face says it all. As the attraction enters its 15th year, Netherworld is once again ranked among the top five in the nation by industry expert Hauntworld.com. Despite the long hours and looming deadlines, Armstrong couldn’t be happier.

Yet occupying the top of Atlanta’s haunted heap brings pressure.

“You have to try and top yourself each year,” Armstrong said, “but that’s also the joy of it. Why do this if you don’t have the chance to create something cool and new? We come back at it every year, and it seems like we spend more time, effort and money, anything we can to get it to be better. We just feel constantly challenged.”

One product of those challenges is this year’s new themes. Netherworld consists of two haunted attractions: The headlining haunt, the Nightmares, takes place upstairs, while Raw Meat occupies the basement area.

Although the Nightmares has a complex story line attached, the basic theme focuses on a group of creatures that can take the form of your worst fears. That means creepy clowns, spiders, snakes and just about any phobia imaginable.

Raw Meat takes guests on a tour through the underbelly of a city where hidden urban terrors reside. It’s also where most of Netherworld’s new additions can be found. Guests hop on a simulated ride in a runaway subway car, cross a suspension bridge above a pool of gators and pass an infestation of hissing cockroaches, among other frights.

“Downstairs is more industrial, bloody and intense,” Armstrong explained. “Upstairs is more classic, traditional, gothic and fantasy-based. If upstairs is ‘Lord of the Rings,’ downstairs is ‘Saw.’”

To bring the scares to life each night, it takes a crew of 100 to 120 actors. That’s not including a tech crew keeping an eye on the effects. Armstrong said he’s lost count of all of the effects running inside Netherworld. It’s somewhere between 200 to 300 different gags.

That isn’t just limited to bigger boos like the 17-foot-tall monster or the spinning vortex tunnel. Netherworld’s attention to detail remains as meticulous as ever, from projections of tiny spiders crawling across the wall to subtle scents pumped into the air.

“We do the little things because people enjoy it,” Armstrong said. “I have this thing I call the 80-20 rule. Eighty percent of the people who come into a haunted house just want to get scared and have a good time. Twenty percent of the people love the little details. They’re immersed in looking at that subtle touch. If you’re going to do a haunted house 100 percent, you’ve got to do it all.”

Doing it all means a yearlong commitment. Even before this season wraps, Armstrong and his cohorts are dreaming up ideas for next year. When the dust settles in November, the Netherworld crew will immediately begin organizational work for the 2012 edition.

But Armstrong isn’t complaining.

“It’s great to have a job that began as a hobby and something you did for fun, and it’s become a career,” he said, again smiling. “You can’t ask for more than that.”

7-11 p.m. Sundays and Nov. 4 and 5; 7 p.m.-midnight Fridays and Saturdays in October, and Oct. 31; 7:30-11 p.m. Mondays-Thursdays. $22 for the Nightmares; $28 for the Nightmares and Raw Meat; $50 speed pass includes both attractions with no waiting. Netherworld at Georgia Antique & Design Center, 6624 Dawson Blvd., Norcross. 404-608-2484, www.fearworld.com.

OTHER HAUNTED ATTRACTIONS IN METRO ATLANTA

MORROW

Frightmore

Without revealing too much, this haunt promises guests will relive their worst nightmares as they cut through the smoke-filled, strobe-lit darkness. For its 2011 show, Frightmore adds a host of new scenes, characters and animatronics. Its season runs Thursdays through Sundays, select Wednesdays in October and Halloween night. The cast returns for a special Wrap Party event on Nov. 5, allowing guests one last shot at the attraction, a meet-and-greet with the actors and more.

7-11 p.m. Thursdays through Sundays; 7 p.m.-midnight Fridays and Saturdays; 7-11 p.m. Oct. 19, 26 and 31. $20; $12 ages 12 and younger. Frightmore, 1912 Mt. Zion Road, Building 1865 C, Morrow. www.frightmore.com.

CONLEY

Atlanta Zombie Apocalypse

Imagine being cast in a zombie flick as humans chased by the undead. This is undoubtedly the closest thing to that without you making it onto George Romero’s call sheet. Now in its second year, Atlanta Zombie Apocalypse transforms a sprawling abandoned truck stop into a haunted attraction. More than 30,000 square feet have been added this year, and it features an all-new production and layout. With flesh-eating zombies on their heels, guests ramble through the grounds, stepping over blood and guts along the way. After the haunt, spring for a little extra, grab a paintball gun and take a shot at zombie actors. Sound too scary? Take a sneak peek as the Weather Channel explores Atlanta Zombie Apocalypse on its haunted attraction special 9 p.m. Oct. 17.

8 p.m. Thursdays-Sundays in October and Oct. 31. $20; $15 zombie shoot; $30 for both. Atlanta Zombie Apocalypse, 4215 Thurman Road, Conley. www.atlantazombie.com.

PONCEY-HIGHLAND

Chambers of Horror

Extreme scares are the gore du jour here. Chambers of Horror proudly proclaims itself an R-rated haunted house. No one under 18 can enter its doors. Just read the premise, and you’ll know why: The experience is a visit to TortureCo, a service that allows twisted high-end clientele the opportunity to torture the innocent. Haunted Attraction magazine ranks it No. 13 among the must-see haunts in the country. Drinkers may opt to get a little courage in a glass at the Splatter Lounge, the attraction’s on-site bar.

8 p.m.-midnight Sundays-Thursdays; 8 p.m.-1 a.m. Fridays and Saturdays; 8 p.m.-3 a.m. Oct. 31. Runs through Oct. 31. $17-$22; $27-$45 for speed and VIP passes. Chambers of Horror at Masquerade, 695 North Ave. N.E., Atlanta. www.chambersofhorroratl.com.