SilverWook said:
2010:The Year We Make Contact explains 2001 a bit. Perhaps too much. ;)
I don't agree with some of the explanations either.
With 2001 I always thought that HAL (as a sentient being) was using his sensors etc to reach out to TMA2 in much the same way the apes reached out to TMA0 and the lunar astronauts reached out to TMA1.
He evolved.
He started killing the crew because they were a threat to him and his goal in life (to complete the mission) just as Moonwatcher started killing to secure his life goal to survive long enough to pass on his genes.
The whole government conspiracy/mental breakdown crap just went counter to everything in the original story.
A bit like those Star Wars prequels (though 2010 is a much better film than the PT).