Get "Armageddon", please.
I will only give you three lines to describe the flick: a negro american president - people being warned of the ominous danger several months before the impact and a national lottery to choose the ones who will go to the "Noah's Ark" (instead of preparing the whole thing secretly and putting aside the normal citizen as it is and as it must be) - Would any person with a minimum sense of reality believe that? - Finally, an unnecessary dawdling of a tedious plot threaded with unsubstantial clichéed characters following the most banal and predictable unpredictability. Make yourself a favor and get Armaggedon, a western-in-space that will make you think of a post-modern version of "The Dirty Dozen" or "The Magnificent Seven". More fun, more epics, and --being a scifi-opera--, more credible by far than this "Flat Impact".