OK, so the story is pretty standard. Also, the characters are not all that interesting, with the notable exception of the teenaged Asagi. But worst of all would be the fact that towards the end of the film, the main characters inexplicably follow the monsters around Tokyo as they fight. If monsters were duking it out in Tokyo, we'd be as far from Tokyo as humanly possible. Barcelona sounds good.
Monsters never attack Barcelona.
The acting is about par for the course as well. We would like to point out here that Steven Seagal's daughter is ten times the actor that her father is, even when all she has to do is look pained and clutch her little Gamera talisman. Effects artist Shinji Higuchi seems to have totally rethought how one brings giant monsters to the screen, and especially how to make a creature as ludicrous as Gamera look cool if not realistic. Realistic isn't really an option when you're talking about Gamera. Gyaos does not fare quite as well, however.