On one hand, you’re thinking Monsters is nothing special. The plot is ho-hum, there’s a love story with decent acting and mediocre dialogue, and an infestation of unintelligent alien monsters ravages the northern third of Mexico. What’s the big deal?

On the other hand, writer, cinematographer, director and visual effects artist Gareth Edwards shot Monsters in three weeks with a small crew out of one van, using a loosely written script that has two actors mostly ad-libbing, and with a budget for cameras and travel of approximately $15,000.

The editing and visual effects took another 13 months, but the film’s overall production cost never exceeded $500,000. Edwards did the majority of the post-production work from his bedroom in the U.K. to complete the film.

EDWARDS DESERVES A NOD FOR MAKING THE MOST WITH WHAT IS CONSIDERED PENNIES IN THE MOVIE-MAKING BUSINESS.

Monsters brings Cloverfield and District 9 to mind. All three are in the monster/alien genre and made with modest budgets. Cloverfield, produced by J.J. Abrams, cost $25 million, while Peter Jackson’s District 9 had $30 million to play with. Edwards deserves a nod for making the most with what is considered pennies in the movie-making business, and without the help of Hollywood’s biggest names.

For the lead roles, Edwards enlisted real-life husband and wife Scoot McNairy and Whitney Able to play the couple trying to get from central Mexico to the safety of the U.S. border. McNairy’s character, photojournalist Andrew Kaulder, is tasked with delivering Able’s character, Samantha Wynden, back to her wealthy father and into the arms of her fiancée.

Never mind that the film doesn’t explain why the two don’t consider catching a flight back to the U.S., but then Monsters could have been edited down to a 10-minute short in which the protagonists sip cocktails and look at the alien monsters out of a plane window during the flight home.

Instead, Samantha and Kaulder, as they call each other, take a train and then hitchhike to the coast to catch a ferry to America. They find out the last ferry of the season leaves in the morning, and considering the insanely expensive passage, they buy one ticket for Samantha and spend a night in a motel within a stone’s throw of the Infected Zone’s southern reach.

But Kaulder gets blackout drunk that night, and both their passports, their money and Samantha’s ferry ticket are stolen. Now Kaulder’s only option for getting Samantha back is to pass through the Infected Zone, where Mexican civilians and guerrilla fighters help them travel through a jungle swarming with aliens. Samantha and Kaulder probably wish they’d thought about going to the airport earlier.

At this point, the audience is still left without a clear sighting of any alien creatures. The extraterrestrials are viewed as partial carcasses, seen through night vision on a TV, or make themselves known with calls that sound like a cross between elephant and whale noises.

During Samantha and Kaulder’s river journey, the boat’s engine breaks down and an alien floats a downed fighter jet to the water’s surface, allowing the pair to flee safely downriver. The alien pulses light through its bioluminescent body, an action apparently in response to Kaulder snapping off a few pictures with his flash on.

This and other clues indicate the aliens have a way of communicating, and that they only attack in response to fear, like when jet planes try to destroy them. One of the guerillas says, “If we don’t bother them, they don’t bother us.”

Something that may bother anyone with an understanding that most of the U.S.-Mexico border is a desert: In Monsters, the jungle infected with aliens reaches all the way to America. Another, even farther reach: The Aztec pyramid that Kaulder and Samantha spend a night on is, inaccurately, within view of the wall separating Mexico and the U.S.

For independent filmmakers without hefty financial backing, it is safe to say Monsters is a grand achievement and an inspiration for those seeking to make a film without Hollywood’s help.

Still, the film would have benefited from a revised, more tightly written script and a professional in a post-production lab, rather than Edwards’ bedroom, do the visual effects’ dirty work.

MONSTERS (2½) Directed by Gareth Edwards • Starring Scoot McNairy, Whitney Able. Rated R. 93 min. At the Osio Cinemas.