One of the better of the early Toho monster epics, the film suffers from a lack of definition. We don't really know where this monster comes from, or why he's so pee-ed off he wants to stomp Tokyo. Also, he never even quite gets to Tokyo, which is major disappointment - what good is a Japanese monster movie where Tokyo doesn't get stomped.
I suspect that the secret to this problem lies in the original score for the film, by the great Akira Ifikube. Godzilla fans should recognize variations on three essential themes for other movies - for "Godzilla", "Rodan", and "Mothra". Yet they are not just borrowed sound-tracks from those films, but actual variations. Apparently Ifikube used composition for this film as a kind of notebook on themes that would later get improved on again and again. My sense is that this is true of the film as a whole, that director Honda and crew used this film as a test-case for work on later films - the kaiju film industry was about to go wide-screen and technicolor in a big way, but the exact formula for the genre had not yet come together. I think they were using this film to get it together.
In its favor, I remark the film is narratively tight, so that not much time is wasted on the back-stories. It is what it is, a straight-out rubber-monster stomp, and begs to be enjoyed for that, and nothing more.
By the way, the subtitled DVD release from Animego has a couple fascinating bonuses to it - an interview with one of the special fx crew, as well as a demonstration of the technique used to manufacture the monster's costume. The film itself is enjoyable, if no great shakes, but bits of film-history like this are priceless.
