The production values are high with really good special effects and a number of spectacular scenes. The opening scene in particular gets it right, starting in the middle of a disaster but focusing on two adults and a child who become key figures in the story. The science has the illusion of reality, playing fair with the viewer, and it appears plausible. Suspension of disbelief is important for a film like this. But so are believable sympathetic characters and it scores well in this respect. Despite the large scale disasters, it's a very human story.
But, and you knew this was coming, its flaws do almost spoil it.
The science is less accurate than it appears. Just one simple example: we know from the recent Japanese earthquake that tsunamis don't appear from nowhere. There are clear signs. Here, however, they do just that and at a couple of hundred feet high. It may be good for drama for not for credibility. I'm not sure that blowing a few hundred holes at the front of the tectonic plate would work either.
It's about half an hour too long. Several scenes go on way too long slowing the pace of the film. Some judicious cutting would have improved the impact no end.
Last and least but nevertheless highly irritating is the inclusion of a couple of mawkish pop songs, one of them completely ruining a genuinely touching scene between two of the characters. After about 30 seconds, I switched off the sound and it was much better -still too long though and the translation of annoying the song of course remained onscreen. The film is subtitled not dubbed, but I don't consider that a flaw. Incidentally, no extras, not even a trailer.
So, lots of good things but several bad. Still, I don't regret buying it.