I have to agree with the first comment and say that this is the best of pre-1995 the Gamera's. I've seen five of them, Guiron and Zigra both being indescribably bad (even when I watched them as a 13 year old I thought so). This one is honestly pretty good, a step-up from the stone age-looking Gamera, which was made in 1965 but looked like it was made in 1954! First off, there isn't too much flashback footage and when it is used, it's actually well-edited and has some pretty cool narration and atmospheric music. There's a random dam attack scene which I still cant figure out why it's there, and then the real story starts with the protagonists finding a jewel that eventually turns into the secondary monster.
Gamera plays a pretty minor second-fiddle this time around, with Barugon, an admittedly more interesting monster, hogging most of the screentime destroying things. I really liked the plotting with the greedy guy accidentally waking the monster with his heat-lamp, and then getting eaten when he ruins the army's plan by trying to steal a giant diamond.
This has the best music and best scenes of destruction of any of the Gamera movies and most of Jun Fukuda's Godzilla films. While it's still Daiei, which most of the time is sub-Toho in every respect, this film shows that around 1966 Daiei actually managed to surpass Toho every now and then effects-wise. Good directing too: the tone is surprisingly mature this time around and it's got a really dark and humorless undercurrent to the whole thing.
My favorite Gamera movie, followed by the... so unintentionally hilarious, it makes me crack up thinking about it... Gamera vs. Gaos.
