Ten-year-old Sydney Shiben stood in the lobby of Nickelodeon Cinemas on Thursday night, clutching two cups of soda while waiting to make her way into the theater. The fourth-grader from Falmouth was about to see herself in a movie, covered with blood and eating another girl’s leg.

She was excited, yet realistic.

“It’ll probably look gross,” Sydney said.

Sydney was among the 120 cast, crew and financial backers of “Night of the Living Deb” who came out Thursday for the film’s world premiere in Portland. Director and York native Kyle Rankin organized the invite-only premiere so local people could see what they helped make, and could celebrate the film’s Portland-ness.

The romantic comedy with zombies was shot at locations all over Portland last June and early July, including coffee shops, restaurants, hotels, yogurt shops, private homes and in the streets. The filmmakers welcomed local involvement so fully they even posted the times and places where scenes would be filmed, so people could watch.

Night of the Living Deb – Official Trailer from Cocksure Entertainment on Vimeo.

“People were just so excited, so welcoming to us,” said Rankin, minutes after stepping out of a limousine near the Nickelodeon on Thursday, along with Ray Wise, one of the film’s stars.

“We had a great time filming here, and Portland is a great background for any kind of film. I don’t see why we wouldn’t film something else here,” said Wise, best known for playing Laura Palmer’s father on the cult TV show “Twin Peaks.”

Though the film is full of zombies, and of recognizable Portland places, it was the comic situations involving Deb (Maria Thayer) and Ryan (Michael Cassidy) that got the biggest rise, and biggest laughs, from the audience Thursday.

After an awkward one-night stand, Ryan tries to get Deb to leave his apartment, only to find Portland in the throes of a zombie apocalypse. They are thrown together by the zombies, fighting for their lives, but arguing like an old married couple. At one point, Deb pulls out a gun and explains that if the two of them get infected by zombies, they should take their own lives. She points to her head and pretends to pull the trigger, then does the same toward Ryan, to show how it would be done. Ryan complains that in her demonstration she shot herself first, then him.

Deb then chides him for worrying about the correct “math for our murder-suicide.”

Rankin, who lived in Portland for about a decade before moving to Los Angeles in 2002, raised half of the $200,000 budget through Kickstarter donations. Despite the paltry budget, the film’s lead players have impressive Hollywood resumes. Cassidy was a star of the TBS sitcom “Men at Work,” while Thayer had a memorable supporting role as a Mormon newlywed in “Forgetting Sarah Marshall.”

Many of the Maine extras and crew who were invited to the premiere Thursday praised Rankin for the way he ran the production last summer, and for letting so many Maine film novices take part.

“It seemed like everything just clicked,” said Patty Jaynes of Portland, a face and body painter who worked as a make-up artist on the film. “It was really an amazing time for everyone.”