Iron Lung is one of those movies where the fear doesn’t come from seeing a monster every five minutes.
The fear comes from not knowing what is out there.
And honestly, that’s what makes this movie so uncomfortable.
The story takes place after an apocalyptic event known as the Quiet Rapture, where the stars and planets mysteriously disappear. Humanity is left struggling to survive, and then something strange is discovered on a barren moon: an ocean of blood.
A convict named Simon is sent down into that ocean in a tiny submarine called the Iron Lung. The submarine is so deep in the blood ocean that its front window has been sealed with metal. Simon can’t simply look outside and see what’s waiting for him.
He has to rely on cameras and instruments.
And that is terrifying.
Because imagine being trapped inside a tiny metal submarine, surrounded by an ocean of blood, knowing that there could be something outside—but you can’t actually see it.
You can only hear it.
You can only imagine it.
And sometimes, what your imagination creates is much scarier than anything the movie could show you.
That’s one thing I really liked about Iron Lung.
The movie understands that horror doesn’t always need to be loud.
Sometimes silence is scarier.
Sometimes a strange sound coming from outside the submarine is scarier than seeing a monster.
Sometimes you just sit there wondering, “What was that?”
And then the movie makes you wait.
That waiting creates the tension.
Markiplier, whose real name is Mark Fischbach, plays Simon and also wrote and directed the movie.
And I have to say, watching him in this role was interesting.
If you’ve watched Markiplier on YouTube before, you already know him as the energetic guy who plays horror games and reacts to terrifying situations.
But here, he has to play someone who is isolated, desperate and trapped.
There is no big group of characters constantly talking.
There is no comfortable environment.
Most of the time, it’s just Simon and this horrible submarine.
And that’s exactly what makes the movie feel so claustrophobic.
You start to feel like you’re inside that submarine with him.
The submarine itself almost becomes a character.
It’s dirty.
It’s cramped.
It’s uncomfortable.
Everything feels like it could break at any moment.
And because Simon is trapped inside it, you know that if something goes wrong, there isn’t really anywhere for him to run.
That’s what makes the situation so frightening.
One thing I found interesting about the story is the way Simon is treated.
He is a convict, and the people sending him into this ocean don’t exactly treat him like someone whose life matters.
He’s basically being sent on an extremely dangerous mission with the promise that, if he succeeds, he might earn his freedom.
But you start wondering:
Do they actually expect him to come back?
Or is this simply a way to get rid of him?
That question makes the whole mission feel even darker.
He’s not just fighting whatever is in the blood ocean.
He’s also fighting the people who put him there.
And then there’s the mystery.
What exactly is in this ocean?
What happened to the universe?
What happened during the Quiet Rapture?
Why did the stars disappear?
And what is that creature?
The movie doesn’t immediately give you all the answers.
Instead, it gives you pieces.
And you have to put them together.
That may frustrate some people because Iron Lung doesn’t explain everything in a straightforward way. Even some reviews have noted that the film’s exposition and mythology can be confusing.
But for me, I think that mystery is part of the appeal.
You’re supposed to feel confused.
Simon doesn’t know everything.
So why should we?
We’re discovering the horror at almost the same time he is.
And that’s what makes the movie different from many modern horror films.
It doesn’t constantly show you what you’re supposed to be afraid of.
It makes you imagine it.
Of course, I also have to talk about the pacing.
This is not a movie where something crazy happens every five minutes.
It takes its time.
Very slowly.
And I can understand why some people might find that boring.
Even critics have pointed out that the pacing can feel slow and that the movie spends a lot of time building atmosphere.
But if you enjoy slow-burn horror, that may actually work for you.
Because the movie is trying to make you uncomfortable before it scares you.
It wants you to sit in that submarine.
It wants you to feel trapped.
It wants you to wonder what’s moving outside.
And when things finally start happening, you’ve already spent enough time in that environment for the danger to feel real.
The Ending
The ending is probably the part that will have people talking.
Without spoiling everything, I will say that the movie doesn’t give you the kind of simple ending where everything is explained and wrapped up neatly.
There are things you’re going to have to think about.
And honestly, I think that’s part of the fun.
You may finish the movie and immediately start asking:
“Wait… what exactly happened?”
“What was that thing?”
“Was Simon ever really going to be allowed to leave?”
“What does the ending actually mean?”
And that’s when you realize the movie has stayed in your head.
For me, that’s one of the things I like about horror.
A movie doesn’t necessarily have to explain everything.
Sometimes it’s better when you’re still thinking about it after the credits.
My Final Thoughts
Iron Lung is not just about a man inside a submarine.
It’s about isolation, fear, desperation and the unknown.
The movie takes a very simple idea—put a man inside a tiny submarine and send him into an ocean of blood and stretches that idea into a psychological horror experience.
And I think the biggest strength of the movie is its atmosphere.
You feel trapped.
You feel isolated.
You know something is probably out there.
But you don’t know exactly what.
And that uncertainty is what makes it scary.
I also think Markiplier deserves credit for taking on such an ambitious project. This was his feature-film writing and directing debut, and the movie was made independently on a relatively small budget.
Is Iron Lung perfect?
No.
The pacing can be slow, some of the explanations can be confusing, and the movie requires patience.
But there is something about it that I appreciate.
It feels like a filmmaker trying to create something different instead of simply copying what every other horror movie is doing.
And that’s probably the biggest thing I took away from it:
Sometimes, you don’t need to see the monster to be afraid of it.
Sometimes, all you need is darkness, a strange sound, and the feeling that something is watching you from the other side of the wall.
And that’s exactly what Iron Lung gives you.
A tiny submarine. An ocean of blood. And something waiting in the darkness.
That’s a terrifying combination.
James
