This review contains spoilers for the original 1954 movie and some hints about the plot of the 2014 remake.

In 1954 the US detonated a hydrogen bomb on Bikini Atoll. The dangerous result was an explosive yield of 15 megatons instead of the expected 6 megatons. For three hours, the blast's radioactive fallout rained down on Lucky Dragon 5, a Japanese fishing boat that was outside the declared danger zone at the time. All the boat's 23 crew members became sick. Its radio operator later died.

That real-life accident, which occurred just nine years after atomic bombs devastated Hiroshima and Nagasaki, caused Japan to increase its push for nuclear disarmament, and prompted worldwide nuclear powers to take a closer, more critical look at atmospheric tests.

The Japanese media were restrained from discussing the dangers of hydrogen bombs and the damage that Tokyo and other cities would suffer in the event of a nuclear attack. Those twin concerns, however, became important themes in a low-budget but highly popular science fiction/horror movie released in Japan that same year: Gojira, better known outside Japan as Godzilla.

A screen shot from the original 1954 Godzilla. CREDIT: Toho Film

The film suggests that hydrogen bomb tests had trapped Godzilla outside its normal habitat and turned the giant beast radioactive. Serving as a symbol for nuclear destruction, Godzilla devastates most of Tokyo in an invincible rampage. Only when a scientist, Daisuke Serizawa (played by Akihiko Hirata), releases a new ultimate weapon, the Oxygen Destroyer, is Godzilla killed.

The 1954 movie, which was not widely known prior to the release of a restored version in 2004, is poignant and sober. I was fortunate enough to see it at the American Film Institute in Silver Spring, Maryland, two weeks ago. The restored movie will be shown at a selection of cinemas around the US during the next few months.

Unlike its 27 Japanese sequels, which hightened the humor and even turned the monster into a hero protecting Japan, the original Godzilla emphasizes mass devastation and the ethics of using powerful weapons. Director Ishiro Honda’s representation of the destruction of Tokyo was evidently influenced by his own experiences during World War II.

The movie’s scientist, Serizawa, originally developed the Oxygen Destroyer for peaceful applications. When he finally gets to use it on Godzilla, he kills himself to prevent his knowledge of the device and from passing into other hands. It's unclear whether Serizawa's drastic action was intended as an example for contemporary atomic scientists to follow.

Godzilla's death is not majestic, but rather pitiful. It is connected, I think, to two points the director was trying to make: That against weapons of mass destruction there is no such thing as mercy, and that atomic power cannot be controlled.

As if to emphasize its connection to real life, the movie is scattered with references to Lucky Dragon 5. The first fishing boat that Godzilla sinks bears the number 5, as does a diving suit used near the end.

The movie is weak in terms of scientific accuracy (though more accurate than Prometheus, for example). Using David Kirby’s scale (see his commentary, "Fistful of science"), I’d rate it 5/10 for scientific authenticity. In terms of imaginative use of science, I’d rate it 8/10. The film concentrates on big ideas of science and ethics, sometimes to the detriment of fleshing out the central characters.

The movie was, and remains, important. Whether it’s enjoyable—Kirby's third criterion—is a different, more subjective, question. I like it, and I re-watch it when I can. I give it 6/10.

The 2014 remake

The original Godzilla could capture and reflect the prevailing mood in Japan toward atomic weapons because it was written, filmed, and shown within a matter of months of the fishing boat disaster. The 2014 US version of Godzilla, which opened last week, has had a much longer gestation period (five years), and a much larger budget ($160 million). Instead of focusing on atomic weapons, the movie considers the safety of all nuclear materials.

Director Gareth Edwards cleverly uses mists and fogs to keep audiences guessing where the giant creature is. He creates neat plot twists to link the original movie to the new one (the opening credits will give you some hints). Edwards effectively builds tension.

A publicity shot for the 2014 remake of Godzilla. CREDIT: Warner Bros. Pictures and Legendary Pictures

Once I recovered from the sheer implausibility of having a 30-story-high radioactive monster stomping around (Godzilla has grown a lot since 1954), I found the movie a lot of fun, although with some wince-inducing moments for physicists.

Using Kirby’s scale again, for scientific authenticity I give it 4/10. Among the movie's scientific weaknesses are floppy disks that can magically survive an electromagnetic pulse, air acting as a catalyst to increase radiation levels, and creatures that can absorb all the ambient radiation. Even if you did see a radioactive reading of zero, would you really take your protective suit off in a contaminated zone?

You also might notice, and be bothered by, the atomic explosion at the beginning of the movie. Rather than use footage of the same blast taken at different angles, the filmmakers showed footage of three different nuclear tests.

Later, Ishiro Serizawa, one of the scientists in the movie (surely named for both the director and the scientist from the first movie), claims that Earth was 10 times more radioactive millions of years in the past than it is today. Currently, Earth produces about 20 TW of thermal power from the decay of uranium and thorium in its crust and mantle. According to most geological models, it is unlikely the power level would have been substantially higher in that time period.

We’ll just entirely skip over whether a helicopter could pick someone up and get out of range of an atom blast within 3–4 minutes. Finally, the yield on the H-bomb used near the end of the film seems closer to that of the B41 gravity bomb (25 megatons), which was retired in 1976, rather than anything in the current stockpile.

On the positive side, the movie suggests that Nevada's Yucca Mountain would be used for storing nuclear waste (which might have been politically feasible for opening day if the movie had appeared when it was written five years ago). One of the lead scientists, played by Bryan Cranston, has a cluttered and messy office that uncannily resembles my own.

In terms of imaginative use of science, I give it less than the original: 6/10. There are certainly big ideas in this film, but the ethical debate is significantly weaker than in the 1954 Godzilla.

For enjoyment, I would give it 8/10. The special effects are impressive, both visually and aurally. I’m not sure that many theater goers will realize how complicated some of the effects are (particularly the computer-generated fog and flames around Godzilla). Despite the impressive human cast, though, the script is probably the weakest link. Godzilla overshadows the actors and their words every time it's on screen.

However, some of the quieter moments stayed with me after the movie ended. In particular, I was struck by the image of a Japanese town years after a major disaster occurs. Although audience members may read the scene as an indirect reference to Fukushima (perhaps still too raw an issue in Japan to treat in a disaster flick), it is the disaster in Chernobyl that I suspect the director was trying to evoke.

The deserted streets, the pack of wild dogs, a town returning to nature—these all warn us of the temporary nature of our infrastructure, and the director’s unspoken hope that we can do better.