From Alejandro Jodorowsky’s “Dune” to Terry Gilliam’s “Watchmen,” cinema history is filled with a tantalizing array of abandoned projects. And amid these fascinating what-if scenarios, one unrealized film has haunted horror fans for almost two decades: George A. Romero’s “Resident Evil.”

In 1998, video game developer Capcom hired Romero, whose landmark classic “Night of the Living Dead” single-handedly created the modern zombie genre, to direct a live-action TV commercial for the game “Resident Evil 2” (known as “Biohazard 2” in Japan). Set in an abandoned jail overrun by the walking dead, the 30-second spot starred Brad Renfro and Adrienne Frantz.

“It was an honor to work with a legend like Romero,” Frantz said. “All of the zombie TV shows and movies that we see today are because of him. He started an entire horror film revolution.”

Frantz was struck by Romero’s dedication to recreating specific images from the game. “Every little detail counted to him,” she said. “I remember he taught me how to pump the shotgun correctly!”

Though it only aired in Japan, the commercial’s cinematic intensity impressed Sony Pictures enough that execs tapped Romero to write and direct a feature adaption of the original game.

Director Rob Kuhns, whose 2013 documentary “Birth of the Living Dead” chronicled the cultural impact of “Night of the Living Dead,” believes that hiring the auteur made good box office sense at the time.

“Having Romero attached gave the film a stamp of legitimacy for horror fans,” Kuhns said. “Back then, if you thought about zombies, you thought of Romero. His involvement guaranteed a certain number of people would come to see the movie.”

The project arrived at a crucial time for Romero. “He had a 10-year period with New Line Cinema where he was paid to develop projects,” Kuhns said. “But he didn’t make anything with them. Everything kept falling through repeatedly.”

Jamie Russell, author of “Book of the Dead: The Complete History of Zombie Cinema,” sees another reason why Romero’s involvement was a wise decision.

“The game’s designer, Shinji Mikami, was a big fan of Romero, and it showed,” Russell said. “It was a game that leant heavily on cinematic camera angles and atmosphere.”

Romero wrote his first draft in six weeks. Set primarily in the game’s eerie Spencer Mansion, the script focused on popular game characters Chris Redfield and Jill Valentine.

Unlike the version that Paul W.S. Anderson eventually wrote and directed in 2002, Romero’s script was faithful to the game’s plot, and featured a menagerie of bizarre creatures (including mutant sharks, giant snakes and a man-eating plant) that gamers had come to love.

This fidelity to the source material was unexpected, considering that Romero had never actually played the game itself. “Romero wasn’t a gamer,” Russell said. “To familiarize himself, he watched a videotape of an assistant playing through it.”

Though some details were changed, the script’s overall tone and structure hewed far closer to the game than Anderson’s post-“Matrix” sci-fi version did.

“The original game was a slow-burn horror story, punctuated by moments of intense terror,” Russell said. “Anderson’s movie, in contrast, took the concept and put it on steroids. It was brash and relentless. At times, you’d be forgiven for thinking he was adapting the ‘Call of Duty’ games.”

Yet despite adhering to the game’s mythology, Sony and Capcom ultimately passed on Romero’s draft. Capcom producer Yoshiki Okamoto bluntly stated at the time: “Romero’s script wasn’t good, so Romero was fired.”

“I know George was really disappointed that he didn’t do it,” Adrienne Frantz said. “Still to this day, I just can’t believe that his version didn’t end up making it.”

According to Jamie Russell, the rejection hit Romero especially hard since “from his point of view, the games had basically ripped-off his Living Dead films to begin with.”

In a happy twist, however, the box office success of Anderson’s film helped reignite audiences’ interest in zombies, paving the way in 2005 for Romero to write and direct “Land of the Dead,” the fourth entry in his Living Dead series. Since then, two more movies — “Diary of the Dead” in 2007 and “Survival of the Dead” in 2009 — have followed.

As the saying goes, you can’t keep a good zombie down.