Review:
Iron Lung is a tense, atmospheric sci-fi horror film that showcases Markiplier’s ambition as a filmmaker, successfully translating the claustrophobic dread of the original video game into a cinematic experience. Set almost entirely inside a cramped submarine navigating an ocean of blood on a distant moon, the film relies more on psychological tension, sound design, and oppressive visuals than traditional jump scares. Markiplier’s performance, while not classically polished, feels raw and emotionally committed, fitting the survival-driven narrative. The production design and lighting create a constant sense of isolation and unease, making viewers feel trapped alongside the protagonist. However, the film’s biggest weakness is its slow pacing; the minimalist setting and limited narrative expansion can feel repetitive for some audiences, especially those unfamiliar with the game. Overall, Iron Lung is a bold, niche horror project that will strongly appeal to fans of atmospheric, slow-burn sci-fi horror and Markiplier’s creative vision, even if it may not satisfy viewers looking for fast-paced or mainstream thrills.
Iron Lung is a 2026 American science fiction horror film written, directed, edited, and starring Mark Fischbach — better known online as Markiplier — in his first major feature film project. Based on the acclaimed 2022 indie horror video game of the same name, the movie takes a bold approach to adapting a minimalist and claustrophobic game into a full-length theatrical experience.
Plot Summary
The film is set in a dystopian, post-apocalyptic future after a catastrophic event called the Quiet Rapture, which has caused the disappearance of stars and most celestial bodies. Humanity survives in isolated space stations and habitats.
The story centers on a convicted man (played by Markiplier) who is forced to pilot a submarine-like vessel known as the Iron Lung through a vast ocean of blood on a barren moon designated AT-5. The mission: explore the deadly liquid sea and return with valuable resources — failure means death.
Performances
Markiplier (Mark Fischbach)
As the lead actor and director, Markiplier delivers a committed and tense performance that fits the film’s oppressive atmosphere. While he may lack the refinement of seasoned dramatic actors, his portrayal of panic, fear, and desperation carries much of the film’s emotional weight.
Supporting Cast
Actors such as Caroline Rose Kaplan and Troy Baker contribute through voice work and limited screen time, adding layers to the subplot and mission control elements. Their involvement helps diversify the sparse cast in this highly focused narrative.
Direction & Adaptation
Markiplier’s direction shows ambition and clarity of vision. His choice to retain the claustrophobic tension from the game — where almost all action occurs within the confined submarine — creates an intimate, if challenging, cinematic experience. However, expanding this concept into a feature film results in slow pacing that some viewers may find dragging or repetitive.
Visuals & Atmosphere
The movie’s visual design excels in creating a oppressive and eerie atmosphere. The submarine’s interior — dim lighting, tight framing, and hostile environment — mirrors the anxiety of the original game, while the blood ocean sequences use practical effects and lighting to invoke visceral dread without relying entirely on CGI.
Sound design amplifies the tension, turning silence into dread and deep ambient noise into psychological fear.
Tone & Style
Iron Lung is less about jump scares and more about lingering dread and psychological horror. It leans into slow-burn terror rather than frantic action, making it ideal for fans of atmospheric horror but potentially frustrating for those expecting constant thrills.
Iron Lung is a tense, atmospheric sci-fi horror film that showcases Markiplier’s ambition as a filmmaker, successfully translating the claustrophobic dread of the original video game into a cinematic experience. Set almost entirely inside a cramped submarine navigating an ocean of blood on a distant moon, the film relies more on psychological tension, sound design, and oppressive visuals than traditional jump scares. Markiplier’s performance feels raw and emotionally committed, fitting the survival-driven narrative, while the production design and lighting constantly reinforce isolation and fear. However, the film’s slow pacing and minimalist storytelling may feel repetitive to some viewers, particularly those unfamiliar with the game. Overall, Iron Lung is a bold, niche horror project that strongly appeals to fans of slow-burn sci-fi and atmospheric storytelling, even if it may not satisfy audiences seeking fast-paced mainstream horror.
The film is rated R for language, intense bloody images, and some gore — true to its horror roots.
Strengths
🧠 Faithful Adaptation
The movie retains the game’s signature claustrophobic horror — a triumph in adapting a minimalist narrative into cinema.
🎥 Atmospheric Tension
Cinematography and sound design work together to build unrelenting tension, making viewers feel trapped alongside the protagonist.
🎭 Passionate Creative Vision
Markiplier’s creative risk — self-funding and self-distributing the film — gives Iron Lung a unique voice in a market dominated by studio horror.
Weaknesses
🕒 Slow Pacing
Many critics and viewers note that the film’s pacing can feel too slow or repetitive, as the story unfolds largely within a single location.
🧩 Limited Story Development
The narrative’s minimal expansion beyond the central premise leaves some audiences wanting deeper character work or more variety in tension and conflict.
🎬 Niche Appeal
Its slow burn and niche themes may not resonate with casual horror fans, especially those unfamiliar with the video game.
Audience and Critical Reception
Critical reception is mixed to positive:
-
Some reviewers appreciate the atmospheric horror and dedicated filmmaking.
-
Others find it boring or overly long, with particular criticism aimed at pacing.
On Rotten Tomatoes and Metacritic, audience scores show strong fan appreciation, especially among Markiplier’s fanbase, with many praising the adaptation and creative effort.
Verdict: Who Will Enjoy Iron Lung?
Watch it if you:
✔️ Are a fan of atmospheric or psychological horror
✔️ Enjoy slow-burn tension and sci-fi horror
✔️ Appreciate indie films and passion projects
✔️ Are familiar with the Iron Lung game
Skip it if you:
❌ Prefer fast-paced stories
❌ Don’t like confined or monotone settings
❌ Want mainstream Hollywood storytelling
