Complete Monster: The greedyOnodera is easily the worst human in the films. As part of a team attempting to retrieve an egg (which they believe to be an opal) for World War II veteran Kano Hirata, Onodera and his two teammates Keisuke and Kawajiri (the latter of whom is the veteran's brother) go to an island and find the egg in a cave. Onodera decides to kill his two partners and keep the egg for himself, despite the fact that his teammates had earlier saved him from being swallowed by quicksand. Onodera lets Kawajiri get fatally stung by a scorpion, and seals Keisuke in the cave to die. When the egg later hatches into the titular Barugon, which goes on to kill thousands of people, Onodera can only think of how he can retrieve the egg (which he still thinks is an opal and believes to have sunk to the bottom of the ocean). When Kano discovers that Onodera killed his brother, Onodera beats the frail old man in a crutch, steals his wallet, and sets the place on fire to kill him and his wife. When Keisuke is revealed to have survived the cave-in and returned with Karen, a girl from the island, Onodera tries to kill him (and likely Karen since she'd be a witness) with a knife. Finally, when he learns that the military is trying to use a diamond to lure Barugon into the water and drown her, Onodera decides to steal the diamond for himself. He shows up with a gun, threatening to shoot anyone who tries to stop him, not caring that the diamond is their best chance at stopping Barugon, or that if she isn't stopped, she will go on to cause even more destruction.
Nightmare Fuel: Kawajiri's death, despite being a little narmy, is pretty horrific. We know that it's coming for a good long time leading up to it, and all the time he's celebrating and talking about how happy he is. Then when he's stung, he dies screaming in pain and begging his friends to save him.
Surprisingly Improved Sequel: It's generally regarded as substantially better than the original black white movie, and by some considered the best of the original Showa era of Gamera films.
Tear Jerker: It's hard not to feel bad for Barugon when Gamera finally drowns it. After everything it did, Barugon was still more or less just an animal, already in misery from the artificial rain bombardments and the self-inflicted wounds from its rainbow.
Ugly Cute: Barugon. Just look at that lizard, he's adorable!