Flatliners is an intriguing science fiction/psychological thriller film drama, originally released in 2017, directed by Niels Arden Oplev, and written by Ben Ripley. This film is a contemporary reboot of the 1990's original, blending elements of science fiction and horror with a deep psychological exploration of guilt, regret, and God's retribution. With an all-star cast including Ellen Page and Diego Luna, the film brings an interesting mix of talents to the table, delivering performances that intensify the suspenseful, dark, and intriguing narrative of the movie.

The film revolves around a group of daring medical students headed by Courtney, played by Ellen Page. Courtney is a brilliant, driven, and extremely curious medical student, always aspiring to unravel the many mysteries that the medical field holds. Diego Luna, starring as Ray, delivers a strong performance portraying a calm and controlled medical student, always acting as the voice of reason that anchors the group together.

In their quest for knowledge, the medical students embark on an experimental journey that borders moral and ethical lines. In an edgy setup in their basement lab, the protagonists decide to explore what lies beyond the confines of death. Courtney, in a bid to understand what happens after death, convinces her fellow students to help her stage her own death and revival, plunging them all into a world of the unknown.

As the storyline progresses, each character in turn goes through the chilling death experiment, flatlining to explore their own version of afterlife. Ellen Page excels in her portrayal of Courtney, combining both academic curiosity and moral apprehension in her quest for answers about death. Diego Luna's Ray, on the other hand, brings a pragmatic perspective to the group's moral compass, with Luna offering a weighty and engaging performance.

What starts out as a bold exploration into the mysteries of the afterlife soon escalates into something far more sinister. As each person comes back from their ‘death experience’, they begin to suffer a series of intense hauntings, each tied to some hidden guilt from their past lives. The movie morphs into a harrowing tale of existential dread and guilt, made more chilling by the vulnerability of their youth and their ambitious careers. It explores the principle that everyone has a past, and no matter how deep we may bury them, the skeletons in their closets tend to claw their way back.

True to its genre, Flatliners incorporates elements of horror, suspense, and psychological thrills into its narrative. It explores themes of life, death, and morality with a spine-chilling tenacity that can be felt in its haunting visuals and eerie soundtrack. The movie presents numerous tense and scary situations, with the fears not stemming from the usual monsters but from the characters' past actions.

Visually, Flatliners is a well-crafted film with high-quality CGI that heightens the tension and brings to life the near-death experiences vividly. The director's choice of using Ultra HD format paints a distinctive picture filled with dark environments and suspense-filled atmosphere. The tagline "You haven’t lived until you’ve died" encapsulates the chilling premise of the film quite aptly.

Alongside the thrilling plot, the film also scores extra points with its diverse casting. With its societally relevant themes, the film's narrative may echo common fears, regrets and guilt, thus connecting with the audience on a deeply personal level.

Flatliners succeeds in asking harrowing questions about ethics, guilt, and the demarcation line between life and death. It offers audiences a unique spin on familiar themes, making it a deeply interesting watch for fans of psychological thrillers and science fiction alike. It might not provide concrete answers to life and death's big questions, but it does open up a world of great cinematic visuals and tense, fast-paced narrative.

To sum it up, Flatliners is a thought-provoking and intense journey into the concept of afterlife, making it an engaging watch for those who love an adrenaline rush.