Finally saw this, and geez, they weren't kidding about it turning into a completely different movie at the end! I can't remember the last time I've seen an ending that felt so completely
cut off from the style and tone of the rest of the movie like that.
As for the movie overall, I thought it was OK. There were some genuinely intense moments here and there, and there was a freshness and originality to many of the action sequences (like at the South Korean airport or in the zombie-infested plane) that I really liked.
But the whole thing flies by so fast-- with zombie attacks that are so quick and bloodless-- that the movie never really has any real weight or impact. It never feels like this is really
happening, but instead like you're just watching a shortened, videogame version of the events or something.