But that's the point. Gojira was intensely focused and serious at the time. Gojira is close to Pan's Labyrinth than to Pacific Rim
Which has nothing to do with whether or not it's a kaiju film. Kaiju is simply the Japanese word for "strange creature," i.e. "monster." Godzilla
is a Japanese movie about a monster, therefore it's a kaiju movie. It's just a more serious kaiju movie than most of its successors.