“The Fallen” opens with a slow-moving shot of seemingly familiar, graffitied forest ruins. A young man — Christian, we later learn — paces the leaf-covered ground with an AK-47 in hand as his small group of survivor comrades cast nervous glances between another.

Most of them knew each other before the outbreak of the infectious disease that destroyed their hometown and left them stranded in the woods. Rebecca, the group’s strong and polarizing leader, is Christian’s stepsister. Irene, an outsider, offers quiet wisdom in the campfire light. Jacob, a friend from high school, is its wildcard loner, while the motherly Catarina cares for Lilly, who yearns for the home and family to which she can never return.

The opening clangs of composer Jake Jurich’s edgy score set the tone for the rest of a film that manages to create suspense and interest until its ending, as the group attempts to survive despite dwindling food supplies and a dangerous wasteland.

Fans of the post-apocalyptic horror/thriller will find a sense of familiarity in the work of director Grant Donghia and his team, who seem to pay homage to this sub genre as a whole in their work. The sirens, graffiti and mask-wearing goons of the “Purge” series, the open field shots of “A Quiet Place,” the dragging, blood-stained pitchfork of “The Crazies” and the nighttime body burning of “It Comes at Night” are all invoked in “The Fallen.”

Like many other films of the genre, family and the disintegration of the group are key themes. The danger seems more likely to come from one of the group members cracking than the disease or those infected by it. Donghia takes his audience back in time through intermittent flashbacks that are managed well throughout the film, and develop the relationships that, by the time the audience meets the characters in the woods, are beginning to crack under the pressure of isolation and terror.

“The Fallen” tasks its cast with navigating the complex and changing emotions of this terror, and as Donghia explained, “being sick or crazy through the entire film.” It rises to the challenge, with the guilt and descent into madness of Mason Hartley’s Christian, Kira-Nicole Barkley’s intense take on Rebecca, and MaryKate Cadden’s naive but courageous Lilly driving its plot forward.

These actors do well to express the terror and confusion of illness and insanity that Donghia and his team aimed to emphasis. But the film’s deepest and most valuable aspect, and how it differentiates itself from others of the genre, is how it presents the process of grief and forgetting after tragedy.

The film is dedicated to Donghia’s mother, who passed away in 2011. He said at its premiere that the film was, in part, a take on the “middle stage” of grief he experienced, when memories fade and the process of forgetting begins. Some of “The Fallen’s” most powerful scenes involve Lilly looking down on the empty farm she once called home, or staring at grainy home movies streaming from a battered projector. This mixes with the panic of responsibility without guidance, as the film’s young characters attempt to navigate a new world and new relationships far from the comforts of home.

“The Fallen” was also shot in central Pennsylvania, and the eerie emptiness of the fall fields, cameos of the Harry Potter room in Pattee Library, and a shot filmed in Wegmans at 1 a.m. add some extra flavor to the film for Penn State students and locals.

These intricacies are reason enough to rule the film a success, but it’s also worth considering the scope and ambition of the project the cast and the production team have completed as students.

There are mistakes — the sound editing is mixed in some places, dialogue occasionally feels unnatural, and vigilant viewers may notice a few inconsistencies. But the film manages to tell a compelling and engaging story with crisp visuals, a professional score, and powerful performances from its cast.