Godzilla vs. Hedora (or the Smog Monster, to the old-school Saturday afternoon horrorshow crowd) is, in some ways, one of the most ambitious films in the G canon. It's got a heavy environmental message, snazzy cinematic tricks including split-screens and animated transition sequences, and attempts at multi-generational appeal (though still heavy on the kid-friendly elements of its era). For the most part, all this baggage manages to mesh together well with the giant monster rampages that we really came looking for. (And if you weren't looking for that, why'd you come here?)
And there's certainly more than enough rampage to go around. Hedora is the first of G's multi-form mutant foes (unless you count Mothra), and each form - giant tadpole, crawling worm, flying pancake, and finally quasi-upright slug-thing - has to get its fair share of screen time wandering from place to place consuming pollutants and transforming them into even nastier chemical attacks. Throw in several good fights against Godzilla and/or the military, and one might almost be willing to forgive the famously embarrassing "Godzilla uses his atomic breath to 'fly'" sequence.
And there's certainly more than enough rampage to go around. Hedora is the first of G's multi-form mutant foes (unless you count Mothra), and each form - giant tadpole, crawling worm, flying pancake, and finally quasi-upright slug-thing - has to get its fair share of screen time wandering from place to place consuming pollutants and transforming them into even nastier chemical attacks. Throw in several good fights against Godzilla and/or the military, and one might almost be willing to forgive the famously embarrassing "Godzilla uses his atomic breath to 'fly'" sequence.