Despite Gigan's terrific entrance as one of the coolest kaiju we've seen and the fun theme park setting. It takes a bit too long for any kaiju to really make an appearance in the film (things only really gets going then).
Wacky, weird and wild. There's so many ideas and visual motifs here, it's just endlessly enjoyable and Hedorah is so repulsive and vindictive. Godzilla using his atomic breath as a makeshift jet pack is an iconic cinematic moment.