what happened??????

Rating: 8/10 (23 November 2005)

What a great film this was? easily in my top ten best ever film. Even though i highly rate, i have no clue to what actually happens. Watched it several times and none the wiser could some one please shed a little light on the ending (actually beginning middle and end. i realise that the world is going to end in 28 days and he goes slightly crazy. What is that creature that keeps popping up now and again............................ help me please it driving me crazy. Also what is that areoplane crash all about, does it have anything to do with any other part of the film.
Thanx people.