Genre
Science Fiction; Horror; War Drama
Spaceships, giant robots, extraterrestrials, and new planets, yeah, none of those show up in the original Godzilla. If that's your bag, the Godzilla franchise still has your back, but you'll have to hit up one of the later entries in the franchise, like Godzilla vs. SpaceGodzilla. That one also has mind control, so…bonus?
Godzilla's only bit of sci-fi tech is the Oxygen Destroyer, and that's really just a stand-in for today's very real weapon of mass destruction, our nuclear arsenal. So, if that's the science half, what's the fiction half?
Well, Godzilla asks us to look at the dangers and responsibilities of scientific advancements in our modern society. The dangers are represented by Godzilla— who, let's not forget, is awakened thanks to a nuclear bomb mixing with a bunch of scientific mumbo-jumbo. Godzilla's rampage represents the death and damage that can be caused by nuclear weapons.
Meanwhile, Serizawa's socially conscious science represents the responsible way to pursue scientific endeavors. Until he can guarantee that his discovery will only benefit humanity, Serizawa refuses to publish his research despite the fact that it would probably net him instant fame.
And at this intersection of science and fiction, we find Godzilla's take on this genre. It's not about the Martians and their tech; it's about an exploration of how science can and should interact in modern society.
Oh, and fire-breathing dinosaurs. It's also about that.
Horror
Godzilla is a little dated, so it can be difficult to see the horror in it. Today, we associate the genre with dark, dirty rooms; oceans of blood and gore; and jump scares galore. But Godzilla doesn't have a single chainsaw murder, and the monster is clearly a dude who is having a hard time seeing through his costume's eye holes.
Yet horror it is. This genre is all about making audiences feel the horror trio: fear, dread, and revulsion. Just imagine a fire-breathing dinosaur stomping its way through your neighborhood, killing your friends and family, and there's nothing you can do to stop it. Sounds pretty terrifying, right? Right.
And that's why Godzilla remains a card-carrying member of the horror genre—even if the special effects haven't quite held up.
War Drama
Godzilla doesn't take place during a particular war, but it does use war as a driving force of its story and themes. The U.S. testing an H-bomb in preparation for a potential war kickstarts the plot by giving Godzilla his fiery temperament (and atomic breath). And Japan fights Godzilla using a modern military arsenal (machine guns, tanks, jets, etc.), but none of these stand up to the nuclear power of the big G.
In this way, the movie uses Godzilla as an analogy for a nuclear war (in a sense, what if the Cold War heated up a bit). Like a nuclear bomb, it will ravage our cities and citizens, and traditional defenses will be unable to stop it. This also ties nicely into the film's pacifist message. After all, if you can't stop the bomb once you let it out, best to just not mess with it in the first place.