Gojira tai Megaro

While the film was all but ignored in Japan, becoming the least attended entry at the box office, it was a huge hit in the United States and is often regarded by fans as one of the main reasons why the Godzilla franchise has become so misunderstood in the west. Its American distributors, Cinema Shares International, built up a large advertising campaign around the movie, and a drastically shortened version that cut the film down to around 40 minutes premiered on prime-time TV on the NBC network. The film's VHS releases were also mistakenly believed to be in public domain, which made it more easily accessible and adding to the movie's notoriety in the US. Despite the film being disliked by the majority of fans, the movie actually received positive reviews from critics upon its initial release in the States. Vincent Canby praised Godzilla's development stating that "the dragon has become St. George" and wrote that the film "demonstrates the rewards of friendships, between humans as well as monsters, and it is gentle." Variety also praised the special effects work and the miniatures work as superb and "reflecting a creative understanding of the camera". The English film critic Phil Hardy also lauded the film's visuals as expertly done.

When Godzilla is bouncing Megalon up and down, the Megalon suit is empty (the legs bend and collapse, showing no one is inside the suit).

The German dub of the film infamously renamed Jet Jaguar to King Kong in an attempt to fool audiences, but it also contained other differences. Most importantly, Goro was changed from being Rokuro's much older brother to his father. And instead of contacting the aliens of M Space Hunter Nebula, the Seatopian people contact a certain "Alpha Base".

Edited from Chikyû Bôeigun (1957)