Having just seen it recently, it's not bad at all IMO. Certainly, there are some U.S. inserts that are played out for laughs such as that talk show in which the participants are discussing the existence of Gamera. If I recall, there was a similar scene like that in "Starship Troopers". Both Albert Dekker and Brian Donlevy are adequate (it was actually their third pairing together in the same feature. "Beau Geste" and "Wake Island" were the other two) and both play their roles straight, in contrast to that of the doubtful senator always whining.
That jet scene in the beginning was very well done I thought. I’ll go as far as saying it was actually better than some of the jet scenes being produced by Toho at that same time.