I will have to give this movie one thumb up and one thumb down.
Thumbs Up/getting it right because unlike many previous attempts Hollywood had at disaster/end of the world Movies, "that wasted an hour plus of time sitting in theaters watching them and the over priced $12.00 + price for the ticket to watch the movie," Hollywood actually got THIS particular take on the end of the world RIGHT in the sense that "IF" something like an unexpected Comet, and its varying sized fragments raining down on the Earth actually DID happen, which COULD actually happen in real life, the drama that unfolded in the movie is socially, psychologically, scientifically, geologically, environmentally speaking ACCURATE!
Sort of/Thumbs DOWN in the sense that the damage caused by the largest fragment hitting the planet shown in the movie is TAME in comparison by what would ACTUALLY happen, and the damage in real life from such a tremendous impact would be FAR GREATER, and far more SEVERE, than how it was portrayed at the end of this movie.
Truth is, If something that large did hit the Planet today, not only would the damage be exactly as how it was shown in this movie but it would be far WORSE in the fact that after such a colossal impact various continents, "like the USA for example," and other currently recognizable land masses, would be unrecognizable and unfamiliar after the event because the impact of such a large mass would not only trigger massive Earth Quakes that would be off the Richter scale and mega tsunamis, but it would also cause tectonic/continental plates to shift dramatically effectively reshaping the familiar continents and land masses we know today into unrecognizable land masses and new continents.
Besides that slight inaccurate depiction of geological events being left out for whatever reason, "probably to give people watching a glimmer of false hope of survival," this WELL DONE movie has the entire chain of events, from the beginning of the impact right down to the horrible and terrifying aspect of human nature disintegrating as the reality sinks in that the world and civilization as they knew it will soon be a distant nightmare that they never will wake up from, was done pretty accurately.
As far as Hollywood disaster/End of the world movies go, this particular one was WELL DONE!