The film was a mixture of the depressing and the humorous. We watch Amin's insanity and paranoia slowly bubble to the surface. While much of what he did was, obviously, pretty disgusting, there were times when he would do things that you couldn't help but laugh at. As an example he got Ugandan folk singers to sing Scottish pop songs at a reception for the Libyan president, christened one son Campbell (or MacKenzie, it isn't made clear which in the film), and crowned himself the King of Scotland.
The doctor is initially charmed by Amin's foibles and agrees with Amin's actions, but as the years progress (he is there from Amin's rise to power to the raid of Entebe airport, where Israeli Army save Jews who have been held hostage there), he realizes that he might be in serious trouble himself and eventually escapes.
All in all it was a very interesting film. I didn't learn a huge amount but Whitaker's Amin was still interesting to watch all the same. Incidentally, Gillian Anderson played a British doctor's wife. Her accent wasn't too bad, but it was almost too "generic posh woman" if that makes any sense.