I love a disaster movie. For this one, I expected the special effects to be good and, given Japan's location, that there'd be some semblance of believability to the plot.
You can almost believe the basic scenario, which is explained in the opening titles. Japan is being dragged under the Pacific plate and this process is suddenly accelerating and about to trigger volcanic eruptions, earthquakes and tsunamis that will destroy the islands long before they sink.
The special effects are well done, though I felt they were cut too short in places. The love-story element was predictable and unnecessarily drawn-out, but that's pretty standard in this genre.
I was less impressed by the way the plot hinges on lack of help from outside Japan. Maybe I've got too much faith in human nature, but I'd hope that, were the world to know that a whole country (especially one as populous and powerful as Japan) were to be obliterated within a year, the world would help. This would be an extraordinary circumstance, and the UN would be drawing up evacuation plans and every available assistance would be given. In this film, no-one seems to be all that interested. The Japanese government goes begging to China and the US and people are evacuated to a number of complaining host countries (while millions of Japanese are dying in strings of disasters).
I understand that this was a Japanese movie, made for a domestic audience, so the slightly nationalistic elements weren't made for me. However, they did end up spoiling it.