Amazing film for 1956: Japanese; in color; fantastic non-optical special effects. (Seriously -- didn't you have an easy time forgetting that's a guy in a giant bird outfit?)
How many other U.S. science fiction films in that era can say that?
Also notable for a 75-minute kaiju film: no monster until halfway through, and the soon-to-be-endlessly-recycled destruction footage doesn't come until the final ten minutes.
I could have done without the human drama with the mineworkers -- this movie's too short to need padding -- but I appreciate them building the mystery as to what this monster is and where it came from. Plus: killer larvae!
Some of it is lost in the dubbed U.S. version, but the Japanese version takes care at the end to make the main characters (and the viewer) care about the Rodans and mourn their end. They're intelligent, non-evil animals. Not exactly Oscar-worthy, but again: guy in giant-bird outfit. It's an impressive achievement.